diff --git a/Cargo.lock b/Cargo.lock
index c14aada54..4dd27c688 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -79,7 +79,7 @@ dependencies = [
 
 [[package]]
 name = "anyhow"
-version = "1.0.23"
+version = "1.0.25"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -130,7 +130,7 @@ version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -307,7 +307,10 @@ name = "bstr"
 version = "0.2.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
+ "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "memchr 2.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex-automata 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -358,6 +361,14 @@ name = "c_linked_list"
 version = "1.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "cast"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "cc"
 version = "1.0.47"
@@ -576,6 +587,42 @@ dependencies = [
  "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "criterion"
+version = "0.2.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "atty 0.2.13 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cast 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "clap 2.33.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "criterion-plot 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "csv 1.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "itertools 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-traits 0.2.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand_core 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand_os 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand_xoshiro 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rayon 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rayon-core 1.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_derive 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_json 1.0.42 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tinytemplate 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "walkdir 2.2.9 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "criterion-plot"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cast 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "itertools 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "crossbeam-channel"
 version = "0.3.9"
@@ -655,6 +702,26 @@ dependencies = [
  "subtle 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "csv"
+version = "1.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "bstr 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "csv-core 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "itoa 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ryu 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "csv-core"
+version = "0.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "memchr 2.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "ct-logs"
 version = "0.6.0"
@@ -669,7 +736,7 @@ version = "0.1.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -708,7 +775,7 @@ dependencies = [
  "clear_on_drop 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "digest 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_core 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "subtle 2.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "subtle 2.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -768,10 +835,11 @@ dependencies = [
 ]
 
 [[package]]
-name = "darwinia-ethereum-bridge"
+name = "darwinia-eth-relay"
 version = "0.2.0"
 dependencies = [
  "ethash 0.4.0 (git+https://github.com/hammeWang/ethash-rs.git?rev=70a4f078)",
+ "merkle-patricia-trie 0.1.0",
  "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rlp 0.4.4 (git+https://github.com/darwinia-network/parity-common.git)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1013,6 +1081,18 @@ dependencies = [
  "sha3 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "ethbloom"
+version = "0.6.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "crunchy 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "fixed-hash 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "impl-rlp 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "impl-serde 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tiny-keccak 1.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "ethbloom"
 version = "0.8.1"
@@ -1026,6 +1106,19 @@ dependencies = [
  "tiny-keccak 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "ethereum-types"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "crunchy 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ethbloom 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ethereum-types-serialize 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "fixed-hash 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
+ "uint 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "ethereum-types"
 version = "0.8.0"
@@ -1039,6 +1132,14 @@ dependencies = [
  "uint 0.8.2 (git+https://github.com/darwinia-network/parity-common.git)",
 ]
 
+[[package]]
+name = "ethereum-types-serialize"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "exit-future"
 version = "0.1.4"
@@ -1078,7 +1179,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "synstructure 0.12.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1122,6 +1223,18 @@ dependencies = [
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "fixed-hash"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "heapsize 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-hex 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "static_assertions 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "fixed-hash"
 version = "0.5.1"
@@ -1314,7 +1427,7 @@ dependencies = [
  "proc-macro-hack 0.5.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1666,12 +1779,12 @@ dependencies = [
  "time 0.1.42 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio 0.1.22 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-buf 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "tokio-executor 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-executor 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-io 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "tokio-reactor 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-reactor 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-tcp 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-threadpool 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)",
- "tokio-timer 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-timer 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "want 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1735,6 +1848,14 @@ dependencies = [
  "rlp 0.4.4 (git+https://github.com/darwinia-network/parity-common.git)",
 ]
 
+[[package]]
+name = "impl-rlp"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "rlp 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "impl-serde"
 version = "0.2.3"
@@ -1758,7 +1879,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1792,6 +1913,14 @@ name = "ipnet"
 version = "2.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "itertools"
+version = "0.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "either 1.5.3 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "itoa"
 version = "0.4.4"
@@ -1817,25 +1946,25 @@ dependencies = [
 
 [[package]]
 name = "jsonrpc-client-transports"
-version = "14.0.3"
+version = "14.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "failure 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)",
  "hyper 0.12.35 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-core 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-pubsub 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-core 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-pubsub 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.42 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio 0.1.22 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 1.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "websocket 0.23.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "websocket 0.24.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "jsonrpc-core"
-version = "14.0.3"
+version = "14.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1847,31 +1976,31 @@ dependencies = [
 
 [[package]]
 name = "jsonrpc-core-client"
-version = "14.0.3"
+version = "14.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "jsonrpc-client-transports 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-client-transports 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "jsonrpc-derive"
-version = "14.0.3"
+version = "14.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro-crate 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "jsonrpc-http-server"
-version = "14.0.3"
+version = "14.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "hyper 0.12.35 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-core 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-server-utils 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-core 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-server-utils 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "net2 0.2.33 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1880,10 +2009,10 @@ dependencies = [
 
 [[package]]
 name = "jsonrpc-pubsub"
-version = "14.0.3"
+version = "14.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "jsonrpc-core 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-core 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1891,12 +2020,12 @@ dependencies = [
 
 [[package]]
 name = "jsonrpc-server-utils"
-version = "14.0.3"
+version = "14.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "bytes 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "globset 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-core 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-core 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio 0.1.22 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1906,11 +2035,11 @@ dependencies = [
 
 [[package]]
 name = "jsonrpc-ws-server"
-version = "14.0.3"
+version = "14.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "jsonrpc-core 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-server-utils 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-core 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-server-utils 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "slab 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2045,7 +2174,7 @@ dependencies = [
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.6.13 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-codec 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "tokio-executor 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-executor 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-io 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "wasm-timer 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -2076,7 +2205,7 @@ dependencies = [
  "rw-stream-sink 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sha2 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.6.13 (registry+https://github.com/rust-lang/crates.io-index)",
- "tokio-executor 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-executor 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-io 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "unsigned-varint 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "untrusted 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2196,7 +2325,7 @@ dependencies = [
  "rand 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.6.13 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-io 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "tokio-reactor 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-reactor 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-udp 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "void 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "wasm-timer 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2325,7 +2454,7 @@ dependencies = [
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-io 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-tcp 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "tokio-timer 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-timer 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -2404,7 +2533,7 @@ dependencies = [
  "hmac-drbg 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "sha2 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "subtle 2.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "subtle 2.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "typenum 1.11.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -2495,7 +2624,7 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "synstructure 0.12.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -2513,6 +2642,9 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 name = "memchr"
 version = "2.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
+]
 
 [[package]]
 name = "memoffset"
@@ -2548,6 +2680,20 @@ dependencies = [
  "srml-system 2.0.0 (git+https://github.com/darwinia-network/substrate.git?branch=darwinia-develop)",
 ]
 
+[[package]]
+name = "merkle-patricia-trie"
+version = "0.1.0"
+dependencies = [
+ "criterion 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ethereum-types 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "hashbrown 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "hex 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "keccak-hash 0.4.1 (git+https://github.com/darwinia-network/parity-common.git)",
+ "rand 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rlp 0.4.4 (git+https://github.com/darwinia-network/parity-common.git)",
+ "uuid 0.7.4 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "merlin"
 version = "1.3.0"
@@ -2577,9 +2723,10 @@ dependencies = [
 
 [[package]]
 name = "mio"
-version = "0.6.19"
+version = "0.6.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
+ "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "fuchsia-zircon 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "fuchsia-zircon-sys 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "iovec 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2599,7 +2746,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "lazycell 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "mio 0.6.19 (registry+https://github.com/rust-lang/crates.io-index)",
+ "mio 0.6.21 (registry+https://github.com/rust-lang/crates.io-index)",
  "slab 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -2610,7 +2757,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "iovec 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
- "mio 0.6.19 (registry+https://github.com/rust-lang/crates.io-index)",
+ "mio 0.6.21 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -2699,7 +2846,7 @@ dependencies = [
  "futures-preview 0.3.0-alpha.19 (registry+https://github.com/rust-lang/crates.io-index)",
  "hex-literal 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "js-sys 0.3.32 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-core 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-core 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "kvdb-memorydb 0.1.0 (git+https://github.com/paritytech/parity-common?rev=b0317f649ab2c665b7987b8475878fc4d2e1f81d)",
  "libp2p 0.13.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2773,7 +2920,7 @@ dependencies = [
 name = "node-rpc"
 version = "2.0.0"
 dependencies = [
- "jsonrpc-core 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-core 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "node-primitives 2.0.0",
  "node-runtime 0.2.0",
  "sr-primitives 2.0.0 (git+https://github.com/darwinia-network/substrate.git?branch=darwinia-develop)",
@@ -2791,7 +2938,7 @@ dependencies = [
  "env_logger 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)",
  "hyper 0.12.35 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-core-client 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-core-client 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "node-primitives 2.0.0",
  "substrate-rpc 2.0.0 (git+https://github.com/darwinia-network/substrate.git?branch=darwinia-develop)",
@@ -2802,7 +2949,7 @@ name = "node-runtime"
 version = "0.2.0"
 dependencies = [
  "darwinia-balances 2.0.0",
- "darwinia-ethereum-bridge 0.2.0",
+ "darwinia-eth-relay 0.2.0",
  "darwinia-kton 0.1.0",
  "darwinia-staking 0.2.0",
  "darwinia-support 0.1.0",
@@ -3076,7 +3223,7 @@ dependencies = [
  "proc-macro-crate 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -3207,7 +3354,7 @@ dependencies = [
  "proc-macro-hack 0.5.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -3307,7 +3454,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -3317,7 +3464,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -3544,6 +3691,15 @@ dependencies = [
  "rand_core 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "rand_xoshiro"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand_core 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "raw-cpuid"
 version = "6.1.0"
@@ -3611,6 +3767,14 @@ dependencies = [
  "thread_local 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "regex-automata"
+version = "0.1.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "regex-syntax"
 version = "0.6.12"
@@ -3761,6 +3925,14 @@ name = "safemem"
 version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "same-file"
+version = "1.0.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "winapi-util 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "schannel"
 version = "0.1.16"
@@ -3782,7 +3954,7 @@ dependencies = [
  "rand_core 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_os 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "sha2 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "subtle 2.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "subtle 2.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "zeroize 0.9.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -3876,7 +4048,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -4015,7 +4187,7 @@ dependencies = [
  "rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "ring 0.16.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "subtle 2.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "subtle 2.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -4070,7 +4242,7 @@ dependencies = [
  "proc-macro-crate 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -4278,9 +4450,9 @@ name = "srml-contracts-rpc"
 version = "2.0.0"
 source = "git+https://github.com/darwinia-network/substrate.git?branch=darwinia-develop#d2c4b0dbd89d9588adcbe97320e27f49ee251411"
 dependencies = [
- "jsonrpc-core 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-core-client 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-derive 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-core 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-core-client 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-derive 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-primitives 2.0.0 (git+https://github.com/darwinia-network/substrate.git?branch=darwinia-develop)",
@@ -4487,7 +4659,7 @@ dependencies = [
  "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "srml-support-procedural-tools 2.0.0 (git+https://github.com/darwinia-network/substrate.git?branch=darwinia-develop)",
- "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -4499,7 +4671,7 @@ dependencies = [
  "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "srml-support-procedural-tools-derive 2.0.0 (git+https://github.com/darwinia-network/substrate.git?branch=darwinia-develop)",
- "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -4509,7 +4681,7 @@ source = "git+https://github.com/darwinia-network/substrate.git?branch=darwinia-
 dependencies = [
  "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -4534,9 +4706,9 @@ name = "srml-system-rpc"
 version = "2.0.0"
 source = "git+https://github.com/darwinia-network/substrate.git?branch=darwinia-develop#d2c4b0dbd89d9588adcbe97320e27f49ee251411"
 dependencies = [
- "jsonrpc-core 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-core-client 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-derive 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-core 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-core-client 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-derive 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -4589,9 +4761,9 @@ name = "srml-transaction-payment-rpc"
 version = "2.0.0"
 source = "git+https://github.com/darwinia-network/substrate.git?branch=darwinia-develop#d2c4b0dbd89d9588adcbe97320e27f49ee251411"
 dependencies = [
- "jsonrpc-core 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-core-client 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-derive 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-core 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-core-client 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-derive 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-primitives 2.0.0 (git+https://github.com/darwinia-network/substrate.git?branch=darwinia-develop)",
@@ -4632,6 +4804,11 @@ name = "stable_deref_trait"
 version = "1.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "static_assertions"
+version = "0.2.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "static_assertions"
 version = "1.1.0"
@@ -4684,7 +4861,7 @@ dependencies = [
  "proc-macro-error 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -4807,7 +4984,7 @@ dependencies = [
  "proc-macro-crate 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -5013,7 +5190,7 @@ source = "git+https://github.com/darwinia-network/substrate.git?branch=darwinia-
 dependencies = [
  "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -5085,8 +5262,8 @@ dependencies = [
  "substrate-network 2.0.0 (git+https://github.com/darwinia-network/substrate.git?branch=darwinia-develop)",
  "substrate-primitives 2.0.0 (git+https://github.com/darwinia-network/substrate.git?branch=darwinia-develop)",
  "substrate-telemetry 2.0.0 (git+https://github.com/darwinia-network/substrate.git?branch=darwinia-develop)",
- "tokio-executor 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "tokio-timer 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-executor 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-timer 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -5148,7 +5325,7 @@ dependencies = [
  "serde_json 1.0.42 (registry+https://github.com/rust-lang/crates.io-index)",
  "substrate-application-crypto 2.0.0 (git+https://github.com/darwinia-network/substrate.git?branch=darwinia-develop)",
  "substrate-primitives 2.0.0 (git+https://github.com/darwinia-network/substrate.git?branch=darwinia-develop)",
- "subtle 2.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "subtle 2.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -5320,8 +5497,8 @@ source = "git+https://github.com/darwinia-network/substrate.git?branch=darwinia-
 dependencies = [
  "futures-preview 0.3.0-alpha.19 (registry+https://github.com/rust-lang/crates.io-index)",
  "hash-db 0.15.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-core 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-pubsub 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-core 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-pubsub 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -5347,10 +5524,10 @@ source = "git+https://github.com/darwinia-network/substrate.git?branch=darwinia-
 dependencies = [
  "derive_more 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures-preview 0.3.0-alpha.19 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-core 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-core-client 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-derive 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-pubsub 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-core 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-core-client 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-derive 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-pubsub 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "parity-scale-codec 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -5376,10 +5553,10 @@ name = "substrate-rpc-servers"
 version = "2.0.0"
 source = "git+https://github.com/darwinia-network/substrate.git?branch=darwinia-develop#d2c4b0dbd89d9588adcbe97320e27f49ee251411"
 dependencies = [
- "jsonrpc-core 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-http-server 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-pubsub 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-ws-server 14.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-core 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-http-server 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-pubsub 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-ws-server 14.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.42 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -5410,7 +5587,7 @@ dependencies = [
  "proc-macro-crate 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -5460,8 +5637,8 @@ dependencies = [
  "substrate-transaction-pool-runtime-api 2.0.0 (git+https://github.com/darwinia-network/substrate.git?branch=darwinia-develop)",
  "sysinfo 0.9.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "target_info 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "tokio-executor 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "tokio-timer 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-executor 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-timer 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -5622,7 +5799,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "subtle"
-version = "2.2.1"
+version = "2.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -5637,7 +5814,7 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "1.0.8"
+version = "1.0.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -5652,7 +5829,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -5782,6 +5959,15 @@ dependencies = [
  "crunchy 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "tinytemplate"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_json 1.0.42 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "tokio"
 version = "0.1.22"
@@ -5789,18 +5975,18 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "bytes 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)",
- "mio 0.6.19 (registry+https://github.com/rust-lang/crates.io-index)",
+ "mio 0.6.21 (registry+https://github.com/rust-lang/crates.io-index)",
  "num_cpus 1.11.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-codec 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-current-thread 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "tokio-executor 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-executor 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-fs 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-io 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "tokio-reactor 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-reactor 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-sync 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-tcp 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-threadpool 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)",
- "tokio-timer 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-timer 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-udp 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-uds 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -5831,7 +6017,7 @@ version = "0.1.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)",
- "tokio-executor 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-executor 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -5847,7 +6033,7 @@ dependencies = [
 
 [[package]]
 name = "tokio-executor"
-version = "0.1.8"
+version = "0.1.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "crossbeam-utils 0.6.6 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -5876,18 +6062,18 @@ dependencies = [
 
 [[package]]
 name = "tokio-reactor"
-version = "0.1.10"
+version = "0.1.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "crossbeam-utils 0.6.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "mio 0.6.19 (registry+https://github.com/rust-lang/crates.io-index)",
+ "mio 0.6.21 (registry+https://github.com/rust-lang/crates.io-index)",
  "num_cpus 1.11.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "slab 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "tokio-executor 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-executor 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-io 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-sync 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -5922,9 +6108,9 @@ dependencies = [
  "bytes 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)",
  "iovec 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "mio 0.6.19 (registry+https://github.com/rust-lang/crates.io-index)",
+ "mio 0.6.21 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-io 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "tokio-reactor 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-reactor 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -5940,18 +6126,18 @@ dependencies = [
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "num_cpus 1.11.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "slab 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "tokio-executor 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-executor 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "tokio-timer"
-version = "0.2.11"
+version = "0.2.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "crossbeam-utils 0.6.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)",
  "slab 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "tokio-executor 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-executor 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -5972,10 +6158,10 @@ dependencies = [
  "bytes 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "mio 0.6.19 (registry+https://github.com/rust-lang/crates.io-index)",
+ "mio 0.6.21 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-codec 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-io 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "tokio-reactor 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-reactor 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -5988,11 +6174,11 @@ dependencies = [
  "iovec 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "mio 0.6.19 (registry+https://github.com/rust-lang/crates.io-index)",
+ "mio 0.6.21 (registry+https://github.com/rust-lang/crates.io-index)",
  "mio-uds 0.6.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-codec 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-io 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "tokio-reactor 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-reactor 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -6087,6 +6273,17 @@ name = "typenum"
 version = "1.11.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "uint"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "crunchy 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "heapsize 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-hex 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "uint"
 version = "0.8.2"
@@ -6195,6 +6392,15 @@ dependencies = [
  "percent-encoding 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "uuid"
+version = "0.7.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "rand 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "vcpkg"
 version = "0.2.7"
@@ -6230,6 +6436,16 @@ name = "void"
 version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "walkdir"
+version = "2.2.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "same-file 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi-util 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "want"
 version = "0.2.0"
@@ -6264,7 +6480,7 @@ dependencies = [
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "wasm-bindgen-shared 0.2.55 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -6296,7 +6512,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "wasm-bindgen-backend 0.2.55 (registry+https://github.com/rust-lang/crates.io-index)",
  "wasm-bindgen-shared 0.2.55 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -6311,12 +6527,12 @@ name = "wasm-bindgen-webidl"
 version = "0.2.55"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "anyhow 1.0.23 (registry+https://github.com/rust-lang/crates.io-index)",
+ "anyhow 1.0.25 (registry+https://github.com/rust-lang/crates.io-index)",
  "heck 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "wasm-bindgen-backend 0.2.55 (registry+https://github.com/rust-lang/crates.io-index)",
  "weedle 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -6329,7 +6545,7 @@ dependencies = [
  "futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)",
  "js-sys 0.3.32 (registry+https://github.com/rust-lang/crates.io-index)",
  "send_wrapper 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "tokio-timer 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-timer 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "wasm-bindgen 0.2.55 (registry+https://github.com/rust-lang/crates.io-index)",
  "web-sys 0.3.32 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -6449,7 +6665,7 @@ name = "web-sys"
 version = "0.3.32"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "anyhow 1.0.23 (registry+https://github.com/rust-lang/crates.io-index)",
+ "anyhow 1.0.25 (registry+https://github.com/rust-lang/crates.io-index)",
  "js-sys 0.3.32 (registry+https://github.com/rust-lang/crates.io-index)",
  "sourcefile 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "wasm-bindgen 0.2.55 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -6483,7 +6699,27 @@ dependencies = [
 
 [[package]]
 name = "websocket"
-version = "0.23.0"
+version = "0.24.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "bytes 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)",
+ "hyper 0.10.16 (registry+https://github.com/rust-lang/crates.io-index)",
+ "native-tls 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-codec 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-io 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-reactor 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-tcp 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-tls 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicase 1.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "url 1.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "websocket-base 0.24.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "websocket-base"
+version = "0.24.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "base64 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -6491,17 +6727,13 @@ dependencies = [
  "byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "bytes 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)",
- "hyper 0.10.16 (registry+https://github.com/rust-lang/crates.io-index)",
  "native-tls 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "sha1 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-codec 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-io 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "tokio-reactor 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-tcp 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-tls 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "unicase 1.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "url 1.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -6576,7 +6808,7 @@ dependencies = [
  "bytes 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "httparse 1.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "mio 0.6.19 (registry+https://github.com/rust-lang/crates.io-index)",
+ "mio 0.6.21 (registry+https://github.com/rust-lang/crates.io-index)",
  "mio-extras 2.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sha-1 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -6649,7 +6881,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "synstructure 0.12.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -6690,7 +6922,7 @@ dependencies = [
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 "checksum scopeguard 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "94258f53601af11e6a49f722422f6e3425c52b06245a5cf9bc09908b174f5e27"
@@ -7117,6 +7363,7 @@ dependencies = [
 "checksum srml-transaction-payment-rpc-runtime-api 2.0.0 (git+https://github.com/darwinia-network/substrate.git?branch=darwinia-develop)" = "<none>"
 "checksum srml-utility 2.0.0 (git+https://github.com/darwinia-network/substrate.git?branch=darwinia-develop)" = "<none>"
 "checksum stable_deref_trait 1.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "dba1a27d3efae4351c8051072d619e3ade2820635c3958d826bfea39d59b54c8"
+"checksum static_assertions 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)" = "c19be23126415861cb3a23e501d34a708f7f9b2183c5252d690941c2e69199d5"
 "checksum static_assertions 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "a2eb9349b6444b326872e140eb1cf5e7c522154d69e7a0ffb0fb81c06b37543f"
 "checksum stream-cipher 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)" = "8131256a5896cabcf5eb04f4d6dacbe1aefda854b0d9896e09cb58829ec5638c"
 "checksum string 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "d24114bfcceb867ca7f71a0d3fe45d45619ec47a6fbfa98cb14e14250bfa5d6d"
@@ -7180,9 +7427,9 @@ dependencies = [
 "checksum substrate-wasm-builder-runner 1.0.4 (git+https://github.com/darwinia-network/substrate.git?branch=darwinia-develop)" = "<none>"
 "checksum substrate-wasm-interface 2.0.0 (git+https://github.com/darwinia-network/substrate.git?branch=darwinia-develop)" = "<none>"
 "checksum subtle 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "2d67a5a62ba6e01cb2192ff309324cb4875d0c451d55fe2319433abe7a05a8ee"
-"checksum subtle 2.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "ab3af2eb31c42e8f0ccf43548232556c42737e01a96db6e1777b0be108e79799"
+"checksum subtle 2.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "7c65d530b10ccaeac294f349038a597e435b18fb456aadd0840a623f83b9e941"
 "checksum syn 0.15.44 (registry+https://github.com/rust-lang/crates.io-index)" = "9ca4b3b69a77cbe1ffc9e198781b7acb0c7365a883670e8f1c1bc66fba79a5c5"
-"checksum syn 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)" = "661641ea2aa15845cddeb97dad000d22070bb5c1fb456b96c1cba883ec691e92"
+"checksum syn 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)" = "f89693ae015201f8de93fd96bde2d065f8bfc3f97ce006d5bc9f900b97c0c7c0"
 "checksum synstructure 0.12.3 (registry+https://github.com/rust-lang/crates.io-index)" = "67656ea1dc1b41b1451851562ea232ec2e5a80242139f7e679ceccfb5d61f545"
 "checksum sysinfo 0.9.6 (registry+https://github.com/rust-lang/crates.io-index)" = "6f4b2468c629cffba39c0a4425849ab3cdb03d9dfacba69684609aea04d08ff9"
 "checksum take_mut 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "f764005d11ee5f36500a149ace24e00e3da98b0158b3e2d53a7495660d3f4d60"
@@ -7198,20 +7445,21 @@ dependencies = [
 "checksum tiny-bip39 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)" = "c1c5676413eaeb1ea35300a0224416f57abc3bd251657e0fafc12c47ff98c060"
 "checksum tiny-keccak 1.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "1d8a021c69bb74a44ccedb824a046447e2c84a01df9e5c20779750acb38e11b2"
 "checksum tiny-keccak 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "2953ca5148619bc99695c1274cb54c5275bbb913c6adad87e72eaf8db9787f69"
+"checksum tinytemplate 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "4574b75faccaacddb9b284faecdf0b544b80b6b294f3d062d325c5726a209c20"
 "checksum tokio 0.1.22 (registry+https://github.com/rust-lang/crates.io-index)" = "5a09c0b5bb588872ab2f09afa13ee6e9dac11e10a0ec9e8e3ba39a5a5d530af6"
 "checksum tokio-buf 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "8fb220f46c53859a4b7ec083e41dec9778ff0b1851c0942b211edb89e0ccdc46"
 "checksum tokio-codec 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "5c501eceaf96f0e1793cf26beb63da3d11c738c4a943fdf3746d81d64684c39f"
 "checksum tokio-current-thread 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "d16217cad7f1b840c5a97dfb3c43b0c871fef423a6e8d2118c604e843662a443"
 "checksum tokio-dns-unofficial 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "82c65483db54eb91b4ef3a9389a3364558590faf30ce473141707c0e16fda975"
-"checksum tokio-executor 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)" = "0f27ee0e6db01c5f0b2973824547ce7e637b2ed79b891a9677b0de9bd532b6ac"
+"checksum tokio-executor 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)" = "ca6df436c42b0c3330a82d855d2ef017cd793090ad550a6bc2184f4b933532ab"
 "checksum tokio-fs 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "3fe6dc22b08d6993916647d108a1a7d15b9cd29c4f4496c62b92c45b5041b7af"
 "checksum tokio-io 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)" = "5090db468dad16e1a7a54c8c67280c5e4b544f3d3e018f0b913b400261f85926"
-"checksum tokio-reactor 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)" = "c56391be9805bc80163151c0b9e5164ee64f4b0200962c346fea12773158f22d"
+"checksum tokio-reactor 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)" = "6732fe6b53c8d11178dcb77ac6d9682af27fc6d4cb87789449152e5377377146"
 "checksum tokio-rustls 0.10.2 (registry+https://github.com/rust-lang/crates.io-index)" = "1df2fa53ac211c136832f530ccb081af9af891af22d685a9493e232c7a359bc2"
 "checksum tokio-sync 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)" = "d06554cce1ae4a50f42fba8023918afa931413aded705b560e29600ccf7c6d76"
 "checksum tokio-tcp 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "1d14b10654be682ac43efee27401d792507e30fd8d26389e1da3b185de2e4119"
 "checksum tokio-threadpool 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)" = "2bd2c6a3885302581f4401c82af70d792bb9df1700e7437b0aeb4ada94d5388c"
-"checksum tokio-timer 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)" = "f2106812d500ed25a4f38235b9cae8f78a09edf43203e16e59c3b769a342a60e"
+"checksum tokio-timer 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)" = "1739638e364e558128461fc1ad84d997702c8e31c2e6b18fb99842268199e827"
 "checksum tokio-tls 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "354b8cd83825b3c20217a9dc174d6a0c67441a2fae5c41bcb1ea6679f6ae0f7c"
 "checksum tokio-udp 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "f02298505547f73e60f568359ef0d016d5acd6e830ab9bc7c4a5b3403440121b"
 "checksum tokio-uds 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)" = "037ffc3ba0e12a0ab4aca92e5234e0dedeb48fddf6ccd260f1f150a36a9f2445"
@@ -7226,6 +7474,7 @@ dependencies = [
 "checksum twox-hash 1.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3bfd5b7557925ce778ff9b9ef90e3ade34c524b5ff10e239c69a42d546d2af56"
 "checksum typeable 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "1410f6f91f21d1612654e7cc69193b0334f909dcf2c790c4826254fbb86f8887"
 "checksum typenum 1.11.2 (registry+https://github.com/rust-lang/crates.io-index)" = "6d2783fe2d6b8c1101136184eb41be8b1ad379e4657050b8aaff0c79ee7575f9"
+"checksum uint 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "082df6964410f6aa929a61ddfafc997e4f32c62c22490e439ac351cec827f436"
 "checksum uint 0.8.2 (git+https://github.com/darwinia-network/parity-common.git)" = "<none>"
 "checksum uint 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)" = "e75a4cdd7b87b28840dba13c483b9a88ee6bbf16ba5c951ee1ecfcf723078e0d"
 "checksum unicase 1.4.2 (registry+https://github.com/rust-lang/crates.io-index)" = "7f4765f83163b74f957c797ad9253caf97f103fb064d3999aea9568d09fc8a33"
@@ -7240,12 +7489,14 @@ dependencies = [
 "checksum untrusted 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "60369ef7a31de49bcb3f6ca728d4ba7300d9a1658f94c727d4cab8c8d9f4aece"
 "checksum url 1.7.2 (registry+https://github.com/rust-lang/crates.io-index)" = "dd4e7c0d531266369519a4aa4f399d748bd37043b00bde1e4ff1f60a120b355a"
 "checksum url 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "75b414f6c464c879d7f9babf951f23bc3743fb7313c081b2e6ca719067ea9d61"
+"checksum uuid 0.7.4 (registry+https://github.com/rust-lang/crates.io-index)" = "90dbc611eb48397705a6b0f6e917da23ae517e4d127123d2cf7674206627d32a"
 "checksum vcpkg 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)" = "33dd455d0f96e90a75803cfeb7f948768c08d70a6de9a8d2362461935698bf95"
 "checksum vec_map 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)" = "05c78687fb1a80548ae3250346c3db86a80a7cdd77bda190189f2d0a0987c81a"
 "checksum vergen 3.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "6aba5e34f93dc7051dfad05b98a18e9156f27e7b431fe1d2398cb6061c0a1dba"
 "checksum version_check 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "914b1a6776c4c929a602fafd8bc742e06365d4bcbe48c30f9cca5824f70dc9dd"
 "checksum version_check 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)" = "078775d0255232fb988e6fccf26ddc9d1ac274299aaedcedce21c6f72cc533ce"
 "checksum void 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "6a02e4885ed3bc0f2de90ea6dd45ebcbb66dacffe03547fadbb0eeae2770887d"
+"checksum walkdir 2.2.9 (registry+https://github.com/rust-lang/crates.io-index)" = "9658c94fa8b940eab2250bd5a457f9c48b748420d71293b165c8cdbe2f55f71e"
 "checksum want 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b6395efa4784b027708f7451087e647ec73cc74f5d9bc2e418404248d679a230"
 "checksum wasi 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b89c3ce4ce14bdc6fb6beaf9ec7928ca331de5df7e5ea278375642a2f478570d"
 "checksum wasm-bindgen 0.2.55 (registry+https://github.com/rust-lang/crates.io-index)" = "29ae32af33bacd663a9a28241abecf01f2be64e6a185c6139b04f18b6385c5f2"
@@ -7267,7 +7518,8 @@ dependencies = [
 "checksum webpki 0.21.0 (registry+https://github.com/rust-lang/crates.io-index)" = "d7e664e770ac0110e2384769bcc59ed19e329d81f555916a6e072714957b81b4"
 "checksum webpki-roots 0.17.0 (registry+https://github.com/rust-lang/crates.io-index)" = "a262ae37dd9d60f60dd473d1158f9fbebf110ba7b6a5051c8160460f6043718b"
 "checksum webpki-roots 0.18.0 (registry+https://github.com/rust-lang/crates.io-index)" = "91cd5736df7f12a964a5067a12c62fa38e1bd8080aff1f80bc29be7c80d19ab4"
-"checksum websocket 0.23.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b255b190f412e45000c35be7fe9b48b39a2ac5eb90d093d421694e5dae8b335c"
+"checksum websocket 0.24.0 (registry+https://github.com/rust-lang/crates.io-index)" = "413b37840b9e27b340ce91b319ede10731de8c72f5bc4cb0206ec1ca4ce581d0"
+"checksum websocket-base 0.24.0 (registry+https://github.com/rust-lang/crates.io-index)" = "5e3810f0d00c4dccb54c30a4eee815e703232819dec7b007db115791c42aa374"
 "checksum weedle 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3bb43f70885151e629e2a19ce9e50bd730fd436cfd4b666894c9ce4de9141164"
 "checksum which 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "b57acb10231b9493c8472b20cb57317d0679a49e0bdbee44b3b803a6473af164"
 "checksum winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "167dc9d6949a9b857f3451275e911c3f44255842c1f7a76f33c55103a909087a"
diff --git a/Cargo.toml b/Cargo.toml
index 95c7068ec..86d720d56 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,6 +7,7 @@ members = [
     "core/merkle-mountain-range",
     "core/fly-client",
     "core/sr-eth-primitives",
+    "core/merkle-patricia-trie",
 
 	"node/cli",
     "node/executor",
@@ -16,7 +17,7 @@ members = [
     "node/runtime",
 
     "srml/balances",
-    "srml/ethereum-bridge",
+    "srml/eth-relay",
     "srml/kton",
     "srml/staking",
     "srml/support"
diff --git a/core/merkle-patricia-trie/Cargo.toml b/core/merkle-patricia-trie/Cargo.toml
new file mode 100644
index 000000000..65a74a46c
--- /dev/null
+++ b/core/merkle-patricia-trie/Cargo.toml
@@ -0,0 +1,30 @@
+[package]
+name = "merkle-patricia-trie"
+version = "0.1.0"
+authors = ["Darwinia Network <hello@darwinia.network>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+rlp = { git = "https://github.com/darwinia-network/parity-common.git", default-features = false }
+hash = { package = "keccak-hash", git = "https://github.com/darwinia-network/parity-common.git", default-features = false }
+hashbrown = { version = "0.6.0" }
+
+[dev-dependencies]
+rand = "0.6.3"
+hex = "0.3.2"
+criterion = "0.2.10"
+ethereum-types = "0.5.2"
+uuid = { version = "0.7", features = ["serde", "v4"] }
+
+[features]
+default = ["std"]
+std = [
+	"rlp/std",
+	"hash/std"
+]
+
+[[bench]]
+name = "trie"
+harness = false
\ No newline at end of file
diff --git a/core/merkle-patricia-trie/benches/trie.rs b/core/merkle-patricia-trie/benches/trie.rs
new file mode 100644
index 000000000..5ee3a89cd
--- /dev/null
+++ b/core/merkle-patricia-trie/benches/trie.rs
@@ -0,0 +1,99 @@
+use std::rc::Rc;
+
+use criterion::{criterion_group, criterion_main, Criterion};
+use merkle_patricia_trie::{MemoryDB, MerklePatriciaTrie, Trie};
+use uuid::Uuid;
+
+fn insert_worse_case_benchmark(c: &mut Criterion) {
+	c.bench_function("insert one", |b| {
+		let mut trie = MerklePatriciaTrie::new(Rc::new(MemoryDB::new()));
+
+		b.iter(|| {
+			let key = Uuid::new_v4().as_bytes().to_vec();
+			let value = Uuid::new_v4().as_bytes().to_vec();
+			trie.insert(key, value).unwrap()
+		})
+	});
+
+	c.bench_function("insert 1k", |b| {
+		let mut trie = MerklePatriciaTrie::new(Rc::new(MemoryDB::new()));
+
+		let (keys, values) = random_data(1000);
+		b.iter(|| {
+			for i in 0..keys.len() {
+				trie.insert(keys[i].clone(), values[i].clone()).unwrap()
+			}
+		});
+	});
+
+	c.bench_function("insert 10k", |b| {
+		let mut trie = MerklePatriciaTrie::new(Rc::new(MemoryDB::new()));
+
+		let (keys, values) = random_data(10000);
+		b.iter(|| {
+			for i in 0..keys.len() {
+				trie.insert(keys[i].clone(), values[i].clone()).unwrap()
+			}
+		});
+	});
+
+	c.bench_function("get based 10k", |b| {
+		let mut trie = MerklePatriciaTrie::new(Rc::new(MemoryDB::new()));
+
+		let (keys, values) = random_data(10000);
+		for i in 0..keys.len() {
+			trie.insert(keys[i].clone(), values[i].clone()).unwrap()
+		}
+
+		b.iter(|| {
+			let key = trie.get(&keys[7777]).unwrap();
+			assert_ne!(key, None);
+		});
+	});
+
+	c.bench_function("remove 1k", |b| {
+		let mut trie = MerklePatriciaTrie::new(Rc::new(MemoryDB::new()));
+
+		let (keys, values) = random_data(1000);
+		for i in 0..keys.len() {
+			trie.insert(keys[i].clone(), values[i].clone()).unwrap()
+		}
+
+		b.iter(|| {
+			for key in keys.iter() {
+				trie.remove(key).unwrap();
+			}
+		});
+	});
+
+	c.bench_function("remove 10k", |b| {
+		let mut trie = MerklePatriciaTrie::new(Rc::new(MemoryDB::new()));
+
+		let (keys, values) = random_data(10000);
+		for i in 0..keys.len() {
+			trie.insert(keys[i].clone(), values[i].clone()).unwrap()
+		}
+
+		b.iter(|| {
+			for key in keys.iter() {
+				trie.remove(key).unwrap();
+			}
+		});
+	});
+}
+
+fn random_data(n: usize) -> (Vec<Vec<u8>>, Vec<Vec<u8>>) {
+	let mut keys = Vec::with_capacity(n);
+	let mut values = Vec::with_capacity(n);
+	for _ in 0..n {
+		let key = Uuid::new_v4().as_bytes().to_vec();
+		let value = Uuid::new_v4().as_bytes().to_vec();
+		keys.push(key);
+		values.push(value);
+	}
+
+	(keys, values)
+}
+
+criterion_group!(benches, insert_worse_case_benchmark);
+criterion_main!(benches);
diff --git a/core/merkle-patricia-trie/src/db.rs b/core/merkle-patricia-trie/src/db.rs
new file mode 100644
index 000000000..00289a732
--- /dev/null
+++ b/core/merkle-patricia-trie/src/db.rs
@@ -0,0 +1,52 @@
+use crate::std::*;
+use hashbrown::HashMap;
+
+#[derive(Debug)]
+pub struct MemoryDB {
+	data: RefCell<HashMap<Vec<u8>, Vec<u8>>>,
+}
+
+impl MemoryDB {
+	pub fn new() -> Self {
+		MemoryDB {
+			data: RefCell::new(HashMap::new()),
+		}
+	}
+
+	pub fn get(&self, key: &[u8]) -> Option<Vec<u8>> {
+		let data = self.data.borrow();
+		if let Some(d) = data.get(key) {
+			Some(d.clone())
+		} else {
+			None
+		}
+	}
+
+	pub fn insert(&self, key: Vec<u8>, value: Vec<u8>) -> Option<Vec<u8>> {
+		self.data.borrow_mut().insert(key, value)
+	}
+
+	pub fn contains(&self, key: &[u8]) -> bool {
+		self.data.borrow().contains_key(key)
+	}
+
+	pub fn remove(&self, key: &[u8]) -> Option<Vec<u8>> {
+		self.data.borrow_mut().remove(key)
+	}
+
+	/// Insert a batch of data into the cache.
+	pub fn insert_batch(&self, keys: Vec<Vec<u8>>, values: Vec<Vec<u8>>) {
+		for i in 0..keys.len() {
+			let key = keys[i].clone();
+			let value = values[i].clone();
+			self.insert(key, value);
+		}
+	}
+
+	/// Remove a batch of data into the cache.
+	pub fn remove_batch(&self, keys: &[Vec<u8>]) {
+		for key in keys {
+			self.remove(key);
+		}
+	}
+}
diff --git a/core/merkle-patricia-trie/src/error.rs b/core/merkle-patricia-trie/src/error.rs
new file mode 100644
index 000000000..6c0047f81
--- /dev/null
+++ b/core/merkle-patricia-trie/src/error.rs
@@ -0,0 +1,30 @@
+use crate::std::*;
+use rlp::DecoderError;
+
+#[derive(Debug)]
+pub enum TrieError {
+	DB(String),
+	Decoder(DecoderError),
+	InvalidData,
+	InvalidStateRoot,
+	InvalidProof,
+}
+
+impl fmt::Display for TrieError {
+	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+		let printable = match *self {
+			TrieError::DB(ref err) => format!("trie error: {:?}", err),
+			TrieError::Decoder(ref err) => format!("trie error: {:?}", err),
+			TrieError::InvalidData => "trie error: invalid data".to_owned(),
+			TrieError::InvalidStateRoot => "trie error: invalid state root".to_owned(),
+			TrieError::InvalidProof => "trie error: invalid proof".to_owned(),
+		};
+		write!(f, "{}", printable)
+	}
+}
+
+impl From<DecoderError> for TrieError {
+	fn from(error: DecoderError) -> Self {
+		TrieError::Decoder(error)
+	}
+}
diff --git a/core/merkle-patricia-trie/src/lib.rs b/core/merkle-patricia-trie/src/lib.rs
new file mode 100644
index 000000000..52d96e639
--- /dev/null
+++ b/core/merkle-patricia-trie/src/lib.rs
@@ -0,0 +1,99 @@
+// Ensure we're `no_std` when compiling for Wasm.
+#![cfg_attr(not(feature = "std"), no_std)]
+
+#[cfg(not(feature = "std"))]
+extern crate alloc;
+#[cfg(not(feature = "std"))]
+extern crate core;
+
+#[cfg(not(feature = "std"))]
+mod std {
+	pub use alloc::borrow::ToOwned;
+	pub use alloc::format;
+	pub use alloc::rc::Rc;
+	pub use alloc::string::String;
+	pub use alloc::vec;
+	pub use alloc::vec::Vec;
+
+	pub use core::cell::RefCell;
+	pub use core::fmt;
+}
+
+#[cfg(feature = "std")]
+mod std {
+	pub use std::cell::RefCell;
+	pub use std::fmt;
+	pub use std::rc::Rc;
+}
+
+mod db;
+mod error;
+mod nibbles;
+mod node;
+mod proof;
+mod tests;
+pub mod trie;
+
+pub use db::MemoryDB;
+pub use error::TrieError;
+pub use proof::Proof;
+pub use trie::{MerklePatriciaTrie, Trie, TrieResult};
+
+/// Generates a trie for a vector of key-value tuples
+///
+/// ```rust
+/// extern crate merkle_patricia_trie as trie;
+/// extern crate hex;
+///
+/// use trie::{Trie, build_trie};
+/// use hex::FromHex;
+///
+/// fn main() {
+/// 	let v = vec![
+/// 		("doe", "reindeer"),
+/// 		("dog", "puppy"),
+/// 		("dogglesworth", "cat"),
+/// 	];
+///
+/// 	let root:Vec<u8> = Vec::from_hex("8aad789dff2f538bca5d8ea56e8abe10f4c7ba3a5dea95fea4cd6e7c3a1168d3").unwrap();
+/// 	assert_eq!(build_trie(v).unwrap().root().unwrap(), root);
+/// }
+/// ```
+pub fn build_trie<I, A, B>(data: I) -> TrieResult<MerklePatriciaTrie>
+where
+	I: IntoIterator<Item = (A, B)>,
+	A: AsRef<[u8]> + Ord,
+	B: AsRef<[u8]>,
+{
+	let memdb = std::Rc::new(MemoryDB::new());
+	let mut trie = MerklePatriciaTrie::new(memdb.clone());
+	data.into_iter().for_each(|(key, value)| {
+		// TODO  the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `core::ops::Try`)
+		trie.insert(key.as_ref().to_vec(), value.as_ref().to_vec());
+	});
+	trie.root()?;
+	Ok(trie)
+}
+
+/// Generates a trie for a vector of values
+///
+/// ```rust
+/// extern crate merkle_patricia_trie as trie;
+/// extern crate hex;
+///
+/// use trie::{Trie, build_order_trie};
+/// use hex::FromHex;
+///
+/// fn main() {
+/// 	let v = &["doe", "reindeer"];
+/// 	let root:Vec<u8> = Vec::from_hex("e766d5d51b89dc39d981b41bda63248d7abce4f0225eefd023792a540bcffee3").unwrap();
+/// 	assert_eq!(build_order_trie(v).unwrap().root().unwrap(), root);
+/// }
+/// ```
+pub fn build_order_trie<I>(data: I) -> TrieResult<MerklePatriciaTrie>
+where
+	I: IntoIterator,
+	I::Item: AsRef<[u8]>,
+{
+	build_trie(data.into_iter().enumerate().map(|(i, v)| (rlp::encode(&i), v)))
+}
diff --git a/core/merkle-patricia-trie/src/nibbles.rs b/core/merkle-patricia-trie/src/nibbles.rs
new file mode 100644
index 000000000..14f4c44ad
--- /dev/null
+++ b/core/merkle-patricia-trie/src/nibbles.rs
@@ -0,0 +1,185 @@
+use crate::std::*;
+use core::cmp::min;
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct Nibbles {
+	hex_data: Vec<u8>,
+}
+
+impl Nibbles {
+	pub fn from_hex(hex: Vec<u8>) -> Self {
+		Nibbles { hex_data: hex }
+	}
+
+	pub fn from_raw(raw: Vec<u8>, is_leaf: bool) -> Self {
+		let mut hex_data = vec![];
+		for item in raw.into_iter() {
+			hex_data.push(item / 16);
+			hex_data.push(item % 16);
+		}
+		if is_leaf {
+			hex_data.push(16);
+		}
+		Nibbles { hex_data }
+	}
+
+	pub fn from_compact(compact: Vec<u8>) -> Self {
+		let mut hex = vec![];
+		let flag = compact[0];
+
+		let mut is_leaf = false;
+		match flag >> 4 {
+			0x0 => {}
+			0x1 => hex.push(flag % 16),
+			0x2 => is_leaf = true,
+			0x3 => {
+				is_leaf = true;
+				hex.push(flag % 16);
+			}
+			_ => panic!("invalid data"),
+		}
+
+		for item in &compact[1..] {
+			hex.push(item / 16);
+			hex.push(item % 16);
+		}
+		if is_leaf {
+			hex.push(16);
+		}
+
+		Nibbles { hex_data: hex }
+	}
+
+	pub fn is_leaf(&self) -> bool {
+		self.hex_data[self.hex_data.len() - 1] == 16
+	}
+
+	pub fn encode_compact(&self) -> Vec<u8> {
+		let mut compact = vec![];
+		let is_leaf = self.is_leaf();
+		let mut hex = if is_leaf {
+			&self.hex_data[0..self.hex_data.len() - 1]
+		} else {
+			&self.hex_data[0..]
+		};
+		// node type    path length    |    prefix    hexchar
+		// --------------------------------------------------
+		// extension    even           |    0000      0x0
+		// extension    odd            |    0001      0x1
+		// leaf         even           |    0010      0x2
+		// leaf         odd            |    0011      0x3
+		let v = if hex.len() % 2 == 1 {
+			let v = 0x10 + hex[0];
+			hex = &hex[1..];
+			v
+		} else {
+			0x00
+		};
+
+		compact.push(v + if is_leaf { 0x20 } else { 0x00 });
+		for i in 0..(hex.len() / 2) {
+			compact.push((hex[i * 2] * 16) + (hex[i * 2 + 1]));
+		}
+
+		compact
+	}
+
+	pub fn encode_raw(&self) -> (Vec<u8>, bool) {
+		let mut raw = vec![];
+		let is_leaf = self.is_leaf();
+		let hex = if is_leaf {
+			&self.hex_data[0..self.hex_data.len() - 1]
+		} else {
+			&self.hex_data[0..]
+		};
+
+		for i in 0..(hex.len() / 2) {
+			raw.push((hex[i * 2] * 16) + (hex[i * 2 + 1]));
+		}
+
+		(raw, is_leaf)
+	}
+
+	pub fn len(&self) -> usize {
+		self.hex_data.len()
+	}
+
+	pub fn is_empty(&self) -> bool {
+		self.len() == 0
+	}
+
+	pub fn at(&self, i: usize) -> usize {
+		self.hex_data[i] as usize
+	}
+
+	pub fn common_prefix(&self, other_partial: &Nibbles) -> usize {
+		let s = min(self.len(), other_partial.len());
+		let mut i = 0usize;
+		while i < s {
+			if self.at(i) != other_partial.at(i) {
+				break;
+			}
+			i += 1;
+		}
+		i
+	}
+
+	pub fn offset(&self, index: usize) -> Nibbles {
+		self.slice(index, self.hex_data.len())
+	}
+
+	pub fn slice(&self, start: usize, end: usize) -> Nibbles {
+		Nibbles::from_hex(self.hex_data[start..end].to_vec())
+	}
+
+	pub fn get_data(&self) -> &[u8] {
+		&self.hex_data
+	}
+
+	pub fn join(&self, b: &Nibbles) -> Nibbles {
+		let mut hex_data = vec![];
+		hex_data.extend_from_slice(self.get_data());
+		hex_data.extend_from_slice(b.get_data());
+		Nibbles::from_hex(hex_data)
+	}
+
+	pub fn extend(&mut self, b: &Nibbles) {
+		self.hex_data.extend_from_slice(b.get_data());
+	}
+
+	pub fn truncate(&mut self, len: usize) {
+		self.hex_data.truncate(len)
+	}
+
+	pub fn pop(&mut self) -> Option<u8> {
+		self.hex_data.pop()
+	}
+
+	pub fn push(&mut self, e: u8) {
+		self.hex_data.push(e)
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+
+	#[test]
+	fn test_nibble() {
+		let n = Nibbles::from_raw(b"key1".to_vec(), true);
+		let compact = n.encode_compact();
+		let n2 = Nibbles::from_compact(compact.clone());
+		let (raw, is_leaf) = n2.encode_raw();
+
+		println!(
+			"source: {:?} \n n: {:?} \n compact: {:?} \n n2: {:?} \n raw: {:?}",
+			b"key1".to_vec(),
+			n,
+			compact,
+			n2,
+			raw
+		);
+		assert_eq!(is_leaf, true);
+		assert_eq!(raw, b"key1");
+	}
+}
diff --git a/core/merkle-patricia-trie/src/node.rs b/core/merkle-patricia-trie/src/node.rs
new file mode 100644
index 000000000..b9dc8b1dc
--- /dev/null
+++ b/core/merkle-patricia-trie/src/node.rs
@@ -0,0 +1,92 @@
+use crate::nibbles::Nibbles;
+use crate::std::*;
+
+#[derive(Debug, Clone)]
+pub enum Node {
+	Empty,
+	Leaf(Rc<RefCell<LeafNode>>),
+	Extension(Rc<RefCell<ExtensionNode>>),
+	Branch(Rc<RefCell<BranchNode>>),
+	Hash(Rc<RefCell<HashNode>>),
+}
+
+impl Node {
+	pub fn from_leaf(key: Nibbles, value: Vec<u8>) -> Self {
+		let leaf = Rc::new(RefCell::new(LeafNode { key, value }));
+		Node::Leaf(leaf)
+	}
+
+	pub fn from_branch(children: [Node; 16], value: Option<Vec<u8>>) -> Self {
+		let branch = Rc::new(RefCell::new(BranchNode { children, value }));
+		Node::Branch(branch)
+	}
+
+	pub fn from_extension(prefix: Nibbles, node: Node) -> Self {
+		let ext = Rc::new(RefCell::new(ExtensionNode { prefix, node }));
+		Node::Extension(ext)
+	}
+
+	pub fn from_hash(hash: Vec<u8>) -> Self {
+		let hash_node = Rc::new(RefCell::new(HashNode { hash }));
+		Node::Hash(hash_node)
+	}
+}
+
+#[derive(Debug)]
+pub struct LeafNode {
+	pub key: Nibbles,
+	pub value: Vec<u8>,
+}
+
+#[derive(Debug)]
+pub struct BranchNode {
+	pub children: [Node; 16],
+	pub value: Option<Vec<u8>>,
+}
+
+impl BranchNode {
+	pub fn insert(&mut self, i: usize, n: Node) {
+		if i == 16 {
+			match n {
+				Node::Leaf(leaf) => {
+					self.value = Some(leaf.borrow().value.clone());
+				}
+				_ => panic!("The n must be leaf node"),
+			}
+		} else {
+			self.children[i] = n
+		}
+	}
+}
+
+#[derive(Debug)]
+pub struct ExtensionNode {
+	pub prefix: Nibbles,
+	pub node: Node,
+}
+
+#[derive(Debug)]
+pub struct HashNode {
+	pub hash: Vec<u8>,
+}
+
+pub fn empty_children() -> [Node; 16] {
+	[
+		Node::Empty,
+		Node::Empty,
+		Node::Empty,
+		Node::Empty,
+		Node::Empty,
+		Node::Empty,
+		Node::Empty,
+		Node::Empty,
+		Node::Empty,
+		Node::Empty,
+		Node::Empty,
+		Node::Empty,
+		Node::Empty,
+		Node::Empty,
+		Node::Empty,
+		Node::Empty,
+	]
+}
diff --git a/core/merkle-patricia-trie/src/proof.rs b/core/merkle-patricia-trie/src/proof.rs
new file mode 100644
index 000000000..400b40c40
--- /dev/null
+++ b/core/merkle-patricia-trie/src/proof.rs
@@ -0,0 +1,52 @@
+use crate::std::*;
+use rlp::{Decodable, DecoderError, Encodable, Rlp, RlpStream};
+
+#[derive(Clone)]
+#[cfg_attr(feature = "std", derive(Debug, PartialEq))]
+pub struct Proof {
+	pub nodes: Vec<Vec<u8>>,
+}
+
+impl Proof {
+	pub fn to_rlp(&self) -> Vec<u8> {
+		rlp::encode(self)
+	}
+
+	pub fn len(&self) -> usize {
+		self.nodes.len()
+	}
+}
+
+impl From<Vec<Vec<u8>>> for Proof {
+	fn from(data: Vec<Vec<u8>>) -> Proof {
+		Proof { nodes: data }
+	}
+}
+
+impl Decodable for Proof {
+	fn decode(r: &Rlp) -> Result<Self, DecoderError> {
+		Ok(Proof { nodes: r.list_at(0)? })
+	}
+}
+
+impl Encodable for Proof {
+	fn rlp_append(&self, s: &mut RlpStream) {
+		s.begin_list(1);
+		s.append_list::<Vec<u8>, Vec<u8>>(&self.nodes);
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+
+	#[test]
+	fn test_encode_decode() {
+		let nodes = vec![vec![0u8], vec![1], vec![2]];
+		let expected = Proof { nodes: nodes };
+		let rlp_proof = rlp::encode(&expected);
+		let out_proof: Proof = rlp::decode(&rlp_proof).unwrap();
+		println!("{:?}", out_proof);
+		assert_eq!(expected, out_proof);
+	}
+}
diff --git a/core/merkle-patricia-trie/src/tests.rs b/core/merkle-patricia-trie/src/tests.rs
new file mode 100644
index 000000000..e64c094e9
--- /dev/null
+++ b/core/merkle-patricia-trie/src/tests.rs
@@ -0,0 +1,657 @@
+#[cfg(test)]
+mod trie_tests {
+	use hex::FromHex;
+	use rand::Rng;
+	use std::rc::Rc;
+
+	use crate::db::MemoryDB;
+	use crate::proof::Proof;
+	use crate::trie::*;
+	use rlp::{self, Rlp};
+
+	fn assert_root(data: Vec<(&[u8], &[u8])>, hash: &str) {
+		let memdb = Rc::new(MemoryDB::new());
+		let mut trie = MerklePatriciaTrie::new(Rc::clone(&memdb));
+		for (k, v) in data.into_iter() {
+			trie.insert(k.to_vec(), v.to_vec()).unwrap();
+		}
+		let r = trie.root().unwrap();
+		let rs = format!("0x{}", hex::encode(r.clone()));
+		assert_eq!(rs.as_str(), hash);
+		let mut trie = MerklePatriciaTrie::from(Rc::clone(&memdb), &r).unwrap();
+		let r2 = trie.root().unwrap();
+		let rs2 = format!("0x{}", hex::encode(r2));
+		assert_eq!(rs2.as_str(), hash);
+	}
+
+	#[test]
+	fn test_root() {
+		// See: https://github.com/ethereum/tests/blob/develop/TrieTests
+		// Copy from trietest.json and trieanyorder.json
+		assert_root(
+			vec![(b"A", b"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa")],
+			"0xd23786fb4a010da3ce639d66d5e904a11dbc02746d1ce25029e53290cabf28ab",
+		);
+		assert_root(
+			vec![(b"doe", b"reindeer"), (b"dog", b"puppy"), (b"dogglesworth", b"cat")],
+			"0x8aad789dff2f538bca5d8ea56e8abe10f4c7ba3a5dea95fea4cd6e7c3a1168d3",
+		);
+		assert_root(
+			vec![
+				(b"do", b"verb"),
+				(b"horse", b"stallion"),
+				(b"doge", b"coin"),
+				(b"dog", b"puppy"),
+			],
+			"0x5991bb8c6514148a29db676a14ac506cd2cd5775ace63c30a4fe457715e9ac84",
+		);
+		assert_root(
+			vec![(b"foo", b"bar"), (b"food", b"bass")],
+			"0x17beaa1648bafa633cda809c90c04af50fc8aed3cb40d16efbddee6fdf63c4c3",
+		);
+
+		assert_root(
+			vec![(b"be", b"e"), (b"dog", b"puppy"), (b"bed", b"d")],
+			"0x3f67c7a47520f79faa29255d2d3c084a7a6df0453116ed7232ff10277a8be68b",
+		);
+		assert_root(
+			vec![(b"test", b"test"), (b"te", b"testy")],
+			"0x8452568af70d8d140f58d941338542f645fcca50094b20f3c3d8c3df49337928",
+		);
+		assert_root(
+			vec![
+				(
+					Vec::from_hex("0045").unwrap().as_slice(),
+					Vec::from_hex("0123456789").unwrap().as_slice(),
+				),
+				(
+					Vec::from_hex("4500").unwrap().as_slice(),
+					Vec::from_hex("9876543210").unwrap().as_slice(),
+				),
+			],
+			"0x285505fcabe84badc8aa310e2aae17eddc7d120aabec8a476902c8184b3a3503",
+		);
+		assert_root(
+			vec![
+				(b"do", b"verb"),
+				(b"ether", b"wookiedoo"),
+				(b"horse", b"stallion"),
+				(b"shaman", b"horse"),
+				(b"doge", b"coin"),
+				(b"ether", b""),
+				(b"dog", b"puppy"),
+				(b"shaman", b""),
+			],
+			"0x5991bb8c6514148a29db676a14ac506cd2cd5775ace63c30a4fe457715e9ac84",
+		);
+		assert_root(
+			vec![
+				(b"do", b"verb"),
+				(b"ether", b"wookiedoo"),
+				(b"horse", b"stallion"),
+				(b"shaman", b"horse"),
+				(b"doge", b"coin"),
+				(b"ether", b""),
+				(b"dog", b"puppy"),
+				(b"shaman", b""),
+			],
+			"0x5991bb8c6514148a29db676a14ac506cd2cd5775ace63c30a4fe457715e9ac84",
+		);
+		assert_root(
+			vec![
+				(
+					Vec::from_hex("04110d816c380812a427968ece99b1c963dfbce6")
+						.unwrap()
+						.as_slice(),
+					b"something",
+				),
+				(
+					Vec::from_hex("095e7baea6a6c7c4c2dfeb977efac326af552d87")
+						.unwrap()
+						.as_slice(),
+					b"something",
+				),
+				(
+					Vec::from_hex("0a517d755cebbf66312b30fff713666a9cb917e0")
+						.unwrap()
+						.as_slice(),
+					b"something",
+				),
+				(
+					Vec::from_hex("24dd378f51adc67a50e339e8031fe9bd4aafab36")
+						.unwrap()
+						.as_slice(),
+					b"something",
+				),
+				(
+					Vec::from_hex("293f982d000532a7861ab122bdc4bbfd26bf9030")
+						.unwrap()
+						.as_slice(),
+					b"something",
+				),
+				(
+					Vec::from_hex("2cf5732f017b0cf1b1f13a1478e10239716bf6b5")
+						.unwrap()
+						.as_slice(),
+					b"something",
+				),
+				(
+					Vec::from_hex("31c640b92c21a1f1465c91070b4b3b4d6854195f")
+						.unwrap()
+						.as_slice(),
+					b"something",
+				),
+				(
+					Vec::from_hex("37f998764813b136ddf5a754f34063fd03065e36")
+						.unwrap()
+						.as_slice(),
+					b"something",
+				),
+				(
+					Vec::from_hex("37fa399a749c121f8a15ce77e3d9f9bec8020d7a")
+						.unwrap()
+						.as_slice(),
+					b"something",
+				),
+				(
+					Vec::from_hex("4f36659fa632310b6ec438dea4085b522a2dd077")
+						.unwrap()
+						.as_slice(),
+					b"something",
+				),
+				(
+					Vec::from_hex("62c01474f089b07dae603491675dc5b5748f7049")
+						.unwrap()
+						.as_slice(),
+					b"something",
+				),
+				(
+					Vec::from_hex("729af7294be595a0efd7d891c9e51f89c07950c7")
+						.unwrap()
+						.as_slice(),
+					b"something",
+				),
+				(
+					Vec::from_hex("83e3e5a16d3b696a0314b30b2534804dd5e11197")
+						.unwrap()
+						.as_slice(),
+					b"something",
+				),
+				(
+					Vec::from_hex("8703df2417e0d7c59d063caa9583cb10a4d20532")
+						.unwrap()
+						.as_slice(),
+					b"something",
+				),
+				(
+					Vec::from_hex("8dffcd74e5b5923512916c6a64b502689cfa65e1")
+						.unwrap()
+						.as_slice(),
+					b"something",
+				),
+				(
+					Vec::from_hex("95a4d7cccb5204733874fa87285a176fe1e9e240")
+						.unwrap()
+						.as_slice(),
+					b"something",
+				),
+				(
+					Vec::from_hex("99b2fcba8120bedd048fe79f5262a6690ed38c39")
+						.unwrap()
+						.as_slice(),
+					b"something",
+				),
+				(
+					Vec::from_hex("a4202b8b8afd5354e3e40a219bdc17f6001bf2cf")
+						.unwrap()
+						.as_slice(),
+					b"something",
+				),
+				(
+					Vec::from_hex("a94f5374fce5edbc8e2a8697c15331677e6ebf0b")
+						.unwrap()
+						.as_slice(),
+					b"something",
+				),
+				(
+					Vec::from_hex("a9647f4a0a14042d91dc33c0328030a7157c93ae")
+						.unwrap()
+						.as_slice(),
+					b"something",
+				),
+				(
+					Vec::from_hex("aa6cffe5185732689c18f37a7f86170cb7304c2a")
+						.unwrap()
+						.as_slice(),
+					b"something",
+				),
+				(
+					Vec::from_hex("aae4a2e3c51c04606dcb3723456e58f3ed214f45")
+						.unwrap()
+						.as_slice(),
+					b"something",
+				),
+				(
+					Vec::from_hex("c37a43e940dfb5baf581a0b82b351d48305fc885")
+						.unwrap()
+						.as_slice(),
+					b"something",
+				),
+				(
+					Vec::from_hex("d2571607e241ecf590ed94b12d87c94babe36db6")
+						.unwrap()
+						.as_slice(),
+					b"something",
+				),
+				(
+					Vec::from_hex("f735071cbee190d76b704ce68384fc21e389fbe7")
+						.unwrap()
+						.as_slice(),
+					b"something",
+				),
+				(
+					Vec::from_hex("04110d816c380812a427968ece99b1c963dfbce6")
+						.unwrap()
+						.as_slice(),
+					b"",
+				),
+				(
+					Vec::from_hex("095e7baea6a6c7c4c2dfeb977efac326af552d87")
+						.unwrap()
+						.as_slice(),
+					b"",
+				),
+				(
+					Vec::from_hex("0a517d755cebbf66312b30fff713666a9cb917e0")
+						.unwrap()
+						.as_slice(),
+					b"",
+				),
+				(
+					Vec::from_hex("24dd378f51adc67a50e339e8031fe9bd4aafab36")
+						.unwrap()
+						.as_slice(),
+					b"",
+				),
+				(
+					Vec::from_hex("293f982d000532a7861ab122bdc4bbfd26bf9030")
+						.unwrap()
+						.as_slice(),
+					b"",
+				),
+				(
+					Vec::from_hex("2cf5732f017b0cf1b1f13a1478e10239716bf6b5")
+						.unwrap()
+						.as_slice(),
+					b"",
+				),
+				(
+					Vec::from_hex("31c640b92c21a1f1465c91070b4b3b4d6854195f")
+						.unwrap()
+						.as_slice(),
+					b"",
+				),
+				(
+					Vec::from_hex("37f998764813b136ddf5a754f34063fd03065e36")
+						.unwrap()
+						.as_slice(),
+					b"",
+				),
+				(
+					Vec::from_hex("37fa399a749c121f8a15ce77e3d9f9bec8020d7a")
+						.unwrap()
+						.as_slice(),
+					b"",
+				),
+				(
+					Vec::from_hex("4f36659fa632310b6ec438dea4085b522a2dd077")
+						.unwrap()
+						.as_slice(),
+					b"",
+				),
+				(
+					Vec::from_hex("62c01474f089b07dae603491675dc5b5748f7049")
+						.unwrap()
+						.as_slice(),
+					b"",
+				),
+				(
+					Vec::from_hex("729af7294be595a0efd7d891c9e51f89c07950c7")
+						.unwrap()
+						.as_slice(),
+					b"",
+				),
+				(
+					Vec::from_hex("83e3e5a16d3b696a0314b30b2534804dd5e11197")
+						.unwrap()
+						.as_slice(),
+					b"",
+				),
+				(
+					Vec::from_hex("8703df2417e0d7c59d063caa9583cb10a4d20532")
+						.unwrap()
+						.as_slice(),
+					b"",
+				),
+				(
+					Vec::from_hex("8dffcd74e5b5923512916c6a64b502689cfa65e1")
+						.unwrap()
+						.as_slice(),
+					b"",
+				),
+				(
+					Vec::from_hex("95a4d7cccb5204733874fa87285a176fe1e9e240")
+						.unwrap()
+						.as_slice(),
+					b"",
+				),
+				(
+					Vec::from_hex("99b2fcba8120bedd048fe79f5262a6690ed38c39")
+						.unwrap()
+						.as_slice(),
+					b"",
+				),
+				(
+					Vec::from_hex("a4202b8b8afd5354e3e40a219bdc17f6001bf2cf")
+						.unwrap()
+						.as_slice(),
+					b"",
+				),
+				(
+					Vec::from_hex("a94f5374fce5edbc8e2a8697c15331677e6ebf0b")
+						.unwrap()
+						.as_slice(),
+					b"",
+				),
+				(
+					Vec::from_hex("a9647f4a0a14042d91dc33c0328030a7157c93ae")
+						.unwrap()
+						.as_slice(),
+					b"",
+				),
+				(
+					Vec::from_hex("aa6cffe5185732689c18f37a7f86170cb7304c2a")
+						.unwrap()
+						.as_slice(),
+					b"",
+				),
+				(
+					Vec::from_hex("aae4a2e3c51c04606dcb3723456e58f3ed214f45")
+						.unwrap()
+						.as_slice(),
+					b"",
+				),
+				(
+					Vec::from_hex("c37a43e940dfb5baf581a0b82b351d48305fc885")
+						.unwrap()
+						.as_slice(),
+					b"",
+				),
+				(
+					Vec::from_hex("d2571607e241ecf590ed94b12d87c94babe36db6")
+						.unwrap()
+						.as_slice(),
+					b"",
+				),
+				(
+					Vec::from_hex("f735071cbee190d76b704ce68384fc21e389fbe7")
+						.unwrap()
+						.as_slice(),
+					b"",
+				),
+			],
+			"0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
+		);
+		assert_root(
+			vec![
+				(
+					Vec::from_hex("0000000000000000000000000000000000000000000000000000000000000045")
+						.unwrap()
+						.as_slice(),
+					Vec::from_hex("22b224a1420a802ab51d326e29fa98e34c4f24ea")
+						.unwrap()
+						.as_slice(),
+				),
+				(
+					Vec::from_hex("0000000000000000000000000000000000000000000000000000000000000046")
+						.unwrap()
+						.as_slice(),
+					Vec::from_hex("67706c2076330000000000000000000000000000000000000000000000000000")
+						.unwrap()
+						.as_slice(),
+				),
+				(
+					Vec::from_hex("0000000000000000000000000000000000000000000000000000001234567890")
+						.unwrap()
+						.as_slice(),
+					Vec::from_hex("697c7b8c961b56f675d570498424ac8de1a918f6")
+						.unwrap()
+						.as_slice(),
+				),
+				(
+					Vec::from_hex("000000000000000000000000697c7b8c961b56f675d570498424ac8de1a918f6")
+						.unwrap()
+						.as_slice(),
+					Vec::from_hex("1234567890").unwrap().as_slice(),
+				),
+				(
+					Vec::from_hex("0000000000000000000000007ef9e639e2733cb34e4dfc576d4b23f72db776b2")
+						.unwrap()
+						.as_slice(),
+					Vec::from_hex("4655474156000000000000000000000000000000000000000000000000000000")
+						.unwrap()
+						.as_slice(),
+				),
+				(
+					Vec::from_hex("000000000000000000000000ec4f34c97e43fbb2816cfd95e388353c7181dab1")
+						.unwrap()
+						.as_slice(),
+					Vec::from_hex("4e616d6552656700000000000000000000000000000000000000000000000000")
+						.unwrap()
+						.as_slice(),
+				),
+				(
+					Vec::from_hex("4655474156000000000000000000000000000000000000000000000000000000")
+						.unwrap()
+						.as_slice(),
+					Vec::from_hex("7ef9e639e2733cb34e4dfc576d4b23f72db776b2")
+						.unwrap()
+						.as_slice(),
+				),
+				(
+					Vec::from_hex("4e616d6552656700000000000000000000000000000000000000000000000000")
+						.unwrap()
+						.as_slice(),
+					Vec::from_hex("ec4f34c97e43fbb2816cfd95e388353c7181dab1")
+						.unwrap()
+						.as_slice(),
+				),
+				(
+					Vec::from_hex("0000000000000000000000000000000000000000000000000000001234567890")
+						.unwrap()
+						.as_slice(),
+					Vec::from_hex("").unwrap().as_slice(),
+				),
+				(
+					Vec::from_hex("000000000000000000000000697c7b8c961b56f675d570498424ac8de1a918f6")
+						.unwrap()
+						.as_slice(),
+					Vec::from_hex("6f6f6f6820736f2067726561742c207265616c6c6c793f000000000000000000")
+						.unwrap()
+						.as_slice(),
+				),
+				(
+					Vec::from_hex("6f6f6f6820736f2067726561742c207265616c6c6c793f000000000000000000")
+						.unwrap()
+						.as_slice(),
+					Vec::from_hex("697c7b8c961b56f675d570498424ac8de1a918f6")
+						.unwrap()
+						.as_slice(),
+				),
+			],
+			"0x9f6221ebb8efe7cff60a716ecb886e67dd042014be444669f0159d8e68b42100",
+		);
+		assert_root(
+			vec![
+				(b"key1aa", b"0123456789012345678901234567890123456789xxx"),
+				(b"key1", b"0123456789012345678901234567890123456789Very_Long"),
+				(b"key2bb", b"aval3"),
+				(b"key2", b"short"),
+				(b"key3cc", b"aval3"),
+				(b"key3", b"1234567890123456789012345678901"),
+			],
+			"0xcb65032e2f76c48b82b5c24b3db8f670ce73982869d38cd39a624f23d62a9e89",
+		);
+		assert_root(
+			vec![(b"abc", b"123"), (b"abcd", b"abcd"), (b"abc", b"abc")],
+			"0x7a320748f780ad9ad5b0837302075ce0eeba6c26e3d8562c67ccc0f1b273298a",
+		);
+	}
+
+	// proof test ref:
+	// - https://github.com/ethereum/go-ethereum/blob/master/trie/proof_test.go
+	// - https://github.com/ethereum/py-trie/blob/master/tests/test_proof.py
+	#[test]
+	fn test_proof_basic() {
+		let memdb = Rc::new(MemoryDB::new());
+		let mut trie = MerklePatriciaTrie::new(Rc::clone(&memdb));
+		trie.insert(b"doe".to_vec(), b"reindeer".to_vec()).unwrap();
+		trie.insert(b"dog".to_vec(), b"puppy".to_vec()).unwrap();
+		trie.insert(b"dogglesworth".to_vec(), b"cat".to_vec()).unwrap();
+		let root = trie.root().unwrap();
+		let r = format!("0x{}", hex::encode(trie.root().unwrap()));
+		assert_eq!(
+			r.as_str(),
+			"0x8aad789dff2f538bca5d8ea56e8abe10f4c7ba3a5dea95fea4cd6e7c3a1168d3"
+		);
+
+		// proof of key exists
+		let proof = trie.get_proof(b"doe").unwrap();
+		let expected = vec![
+            "e5831646f6a0db6ae1fda66890f6693f36560d36b4dca68b4d838f17016b151efe1d4c95c453",
+            "f83b8080808080ca20887265696e6465657280a037efd11993cb04a54048c25320e9f29c50a432d28afdf01598b2978ce1ca3068808080808080808080",
+        ];
+		assert_eq!(
+			proof.clone().nodes.into_iter().map(hex::encode).collect::<Vec<_>>(),
+			expected
+		);
+		let value = MerklePatriciaTrie::verify_proof(root.clone(), b"doe", proof).unwrap();
+		assert_eq!(value, Some(b"reindeer".to_vec()));
+
+		// proof of key not exist
+		let proof = trie.get_proof(b"dogg").unwrap();
+		let expected = vec![
+            "e5831646f6a0db6ae1fda66890f6693f36560d36b4dca68b4d838f17016b151efe1d4c95c453",
+            "f83b8080808080ca20887265696e6465657280a037efd11993cb04a54048c25320e9f29c50a432d28afdf01598b2978ce1ca3068808080808080808080",
+            "e4808080808080ce89376c6573776f72746883636174808080808080808080857075707079",
+        ];
+		assert_eq!(
+			proof.clone().nodes.into_iter().map(hex::encode).collect::<Vec<_>>(),
+			expected
+		);
+		let value = MerklePatriciaTrie::verify_proof(root.clone(), b"dogg", proof).unwrap();
+		assert_eq!(value, None);
+
+		// empty proof
+		let proof = vec![];
+		let value = MerklePatriciaTrie::verify_proof(root.clone(), b"doe", proof.into());
+		assert_eq!(value.is_err(), true);
+
+		// bad proof
+		let proof = vec![b"aaa".to_vec(), b"ccc".to_vec()];
+		let value = MerklePatriciaTrie::verify_proof(root.clone(), b"doe", proof.into());
+		assert_eq!(value.is_err(), true);
+	}
+
+	#[test]
+	fn test_proof_random() {
+		let memdb = Rc::new(MemoryDB::new());
+		let mut trie = MerklePatriciaTrie::new(Rc::clone(&memdb));
+		let mut rng = rand::thread_rng();
+		let mut keys = vec![];
+		for _ in 0..100 {
+			let random_bytes: Vec<u8> = (0..rng.gen_range(2, 30)).map(|_| rand::random::<u8>()).collect();
+			trie.insert(random_bytes.to_vec(), random_bytes.clone()).unwrap();
+			keys.push(random_bytes.clone());
+		}
+		for k in keys.clone().into_iter() {
+			trie.insert(k.clone(), k.clone()).unwrap();
+		}
+		let root = trie.root().unwrap();
+		for k in keys.into_iter() {
+			let proof = trie.get_proof(&k).unwrap();
+			let value = MerklePatriciaTrie::verify_proof(root.clone(), &k, proof)
+				.unwrap()
+				.unwrap();
+			assert_eq!(value, k);
+		}
+	}
+
+	#[test]
+	fn test_proof_empty_trie() {
+		let memdb = Rc::new(MemoryDB::new());
+		let mut trie = MerklePatriciaTrie::new(Rc::clone(&memdb));
+		trie.root().unwrap();
+		let proof = trie.get_proof(b"not-exist").unwrap();
+		assert_eq!(proof.len(), 0);
+	}
+
+	#[test]
+	fn test_proof_one_element() {
+		let memdb = Rc::new(MemoryDB::new());
+		let mut trie = MerklePatriciaTrie::new(Rc::clone(&memdb));
+		trie.insert(b"k".to_vec(), b"v".to_vec()).unwrap();
+		let root = trie.root().unwrap();
+		let proof = trie.get_proof(b"k").unwrap();
+		assert_eq!(proof.len(), 1);
+		let value = MerklePatriciaTrie::verify_proof(root.clone(), b"k", proof.clone()).unwrap();
+		assert_eq!(value, Some(b"v".to_vec()));
+
+		// remove key does not affect the verify process
+		trie.remove(b"k").unwrap();
+		let _root = trie.root().unwrap();
+		let value = MerklePatriciaTrie::verify_proof(root.clone(), b"k", proof.clone()).unwrap();
+		assert_eq!(value, Some(b"v".to_vec()));
+	}
+
+	#[test]
+	fn test_ethereum_receipts_proof() {
+		let rlp_proof: Vec<u8> = Vec::from_hex("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").unwrap();
+		let expected: Vec<u8> = Vec::from_hex("f9010901835cdb6eb9010000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000c0").unwrap();
+		let root = Vec::from_hex("7fa081e3e33e53c4d09ae691af3853bb73a7e02c856104fe843172abab85df7b").unwrap();
+
+		let proof: Proof = rlp::decode(&rlp_proof).unwrap();
+		let key = rlp::encode(&1usize);
+		let value = MerklePatriciaTrie::verify_proof(root.clone(), &key, proof.clone()).unwrap();
+		assert!(value.is_some());
+		assert_eq!(value.unwrap(), expected);
+	}
+
+	#[test]
+	fn test_ethereum_receipts_build_proof() {
+		// transaction hash 0xb04fcb9822eb21b5ffdbf89df076de58469af66d23c86abe30266e5d3c5e0db2   in ropsten
+		// build trie
+		let data = vec![
+            Vec::from_hex("f90184018261beb9010000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000040000000000000000000000000000000000000000000000000000000040000000000000000000000800000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000800000020000000000000000000000000000000000f87bf87994095c5cbf4937d0a21f6f395194e95b6ebe8616b9e1a06ef95f06320e7a25a04a175ca677b7052bdd97131872c2192525a629f51be770b8400000000000000000000000002e0a521fe69c14d99c8d236d8c3cd5353cc44e720000000000000000000000000000000000000000000000000000000000000000").unwrap(),
+            Vec::from_hex("f9010901835cdb6eb9010000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000c0").unwrap(),
+        ];
+		let hash = "0x7fa081e3e33e53c4d09ae691af3853bb73a7e02c856104fe843172abab85df7b";
+
+		let memdb = Rc::new(MemoryDB::new());
+		let mut trie = MerklePatriciaTrie::new(Rc::clone(&memdb));
+		for (k, v) in data.clone().into_iter().enumerate().map(|(i, v)| (rlp::encode(&i), v)) {
+			trie.insert(k.to_vec(), v.to_vec()).unwrap();
+		}
+		let r = trie.root().unwrap();
+		let rs = format!("0x{}", hex::encode(r.clone()));
+
+		assert_eq!(rs.as_str(), hash);
+
+		// check proof
+		let key = rlp::encode(&1usize);
+		let proof = trie.get_proof(&key).unwrap();
+		let value = MerklePatriciaTrie::verify_proof(r.clone(), &key, proof.clone()).unwrap();
+
+		assert_eq!(value.unwrap(), data[1]);
+	}
+}
diff --git a/core/merkle-patricia-trie/src/trie.rs b/core/merkle-patricia-trie/src/trie.rs
new file mode 100644
index 000000000..a1ba47ecf
--- /dev/null
+++ b/core/merkle-patricia-trie/src/trie.rs
@@ -0,0 +1,1058 @@
+use crate::std::*;
+use hash::keccak;
+use hashbrown::{HashMap, HashSet};
+use rlp::{Prototype, Rlp, RlpStream};
+
+use crate::db::MemoryDB;
+use crate::error::TrieError;
+use crate::nibbles::Nibbles;
+use crate::node::{empty_children, BranchNode, Node};
+use crate::proof::Proof;
+
+pub type TrieResult<T> = Result<T, TrieError>;
+
+const LENGTH: usize = 32;
+
+#[derive(Debug)]
+pub struct MerklePatriciaTrie {
+	root: Node,
+	root_hash: Vec<u8>,
+	pub db: Rc<MemoryDB>,
+	cache: RefCell<HashMap<Vec<u8>, Vec<u8>>>,
+	passing_keys: RefCell<HashSet<Vec<u8>>>,
+	gen_keys: RefCell<HashSet<Vec<u8>>>,
+}
+
+impl MerklePatriciaTrie {
+	pub fn new(db: Rc<MemoryDB>) -> Self {
+		Self {
+			root: Node::Empty,
+			root_hash: hasher_digest(&rlp::NULL_RLP.to_vec()),
+
+			cache: RefCell::new(HashMap::new()),
+			passing_keys: RefCell::new(HashSet::new()),
+			gen_keys: RefCell::new(HashSet::new()),
+
+			db,
+		}
+	}
+
+	pub fn from(db: Rc<MemoryDB>, root: &[u8]) -> TrieResult<Self> {
+		match db.get(&root) {
+			Some(data) => {
+				let mut trie = Self {
+					root: Node::Empty,
+					root_hash: root.to_vec(),
+
+					cache: RefCell::new(HashMap::new()),
+					passing_keys: RefCell::new(HashSet::new()),
+					gen_keys: RefCell::new(HashSet::new()),
+
+					db,
+				};
+
+				trie.root = trie.decode_node(&data)?;
+				Ok(trie)
+			}
+			None => Err(TrieError::InvalidStateRoot),
+		}
+	}
+}
+
+fn hasher_digest(data: &[u8]) -> Vec<u8> {
+	keccak(data).0.to_vec()
+}
+
+pub trait Trie {
+	/// Returns the value for key stored in the trie.
+	fn get(&self, key: &[u8]) -> TrieResult<Option<Vec<u8>>>;
+
+	/// Checks that the key is present in the trie
+	fn contains(&self, key: &[u8]) -> TrieResult<bool>;
+
+	/// Inserts value into trie and modifies it if it exists
+	fn insert(&mut self, key: Vec<u8>, value: Vec<u8>) -> TrieResult<bool>;
+
+	/// Removes any existing value for key from the trie.
+	fn remove(&mut self, key: &[u8]) -> TrieResult<bool>;
+
+	/// Saves all the nodes in the db, clears the cache data, recalculates the root.
+	/// Returns the root hash of the trie.
+	fn root(&mut self) -> TrieResult<Vec<u8>>;
+
+	/// Prove constructs a merkle proof for key. The result contains all encoded nodes
+	/// on the path to the value at key. The value itself is also included in the last
+	/// node and can be retrieved by verifying the proof.
+	///
+	/// If the trie does not contain a value for key, the returned proof contains all
+	/// nodes of the longest existing prefix of the key (at least the root node), ending
+	/// with the node that proves the absence of the key.
+	fn get_proof(&self, key: &[u8]) -> TrieResult<Proof>;
+
+	/// return value if key exists, None if key not exist, Error if proof is wrong
+	fn verify_proof(root_hash: Vec<u8>, key: &[u8], proof: Proof) -> TrieResult<Option<Vec<u8>>>;
+}
+
+impl Trie for MerklePatriciaTrie {
+	/// Returns the value for key stored in the trie.
+	fn get(&self, key: &[u8]) -> TrieResult<Option<Vec<u8>>> {
+		self.get_at(self.root.clone(), &Nibbles::from_raw(key.to_vec(), true))
+	}
+
+	/// Checks that the key is present in the trie
+	fn contains(&self, key: &[u8]) -> TrieResult<bool> {
+		Ok(self
+			.get_at(self.root.clone(), &Nibbles::from_raw(key.to_vec(), true))?
+			.map_or(false, |_| true))
+	}
+
+	/// Inserts value into trie and modifies it if it exists
+	fn insert(&mut self, key: Vec<u8>, value: Vec<u8>) -> TrieResult<bool> {
+		if value.is_empty() {
+			self.remove(&key)?;
+			return Ok(false);
+		}
+		let root = self.root.clone();
+		self.root = self.insert_at(root, Nibbles::from_raw(key, true), value.to_vec())?;
+		Ok(true)
+	}
+
+	/// Removes any existing value for key from the trie.
+	fn remove(&mut self, key: &[u8]) -> TrieResult<bool> {
+		let (n, removed) = self.delete_at(self.root.clone(), &Nibbles::from_raw(key.to_vec(), true))?;
+		self.root = n;
+		Ok(removed)
+	}
+
+	/// Saves all the nodes in the db, clears the cache data, recalculates the root.
+	/// Returns the root hash of the trie.
+	fn root(&mut self) -> TrieResult<Vec<u8>> {
+		self.commit()
+	}
+
+	/// Prove constructs a merkle proof for key. The result contains all encoded nodes
+	/// on the path to the value at key. The value itself is also included in the last
+	/// node and can be retrieved by verifying the proof.
+	///
+	/// If the trie does not contain a value for key, the returned proof contains all
+	/// nodes of the longest existing prefix of the key (at least the root node), ending
+	/// with the node that proves the absence of the key.
+	fn get_proof(&self, key: &[u8]) -> TrieResult<Proof> {
+		let mut path = self.get_path_at(self.root.clone(), &Nibbles::from_raw(key.to_vec(), true))?;
+		match self.root {
+			Node::Empty => {}
+			_ => path.push(self.root.clone()),
+		}
+		Ok(Proof {
+			nodes: path.into_iter().rev().map(|n| self.encode_raw(n)).collect(),
+		})
+	}
+
+	/// return value if key exists, None if key not exist, Error if proof is wrong
+	///
+	/// insert data to memory db, and check root. if value exists, means ok .
+	fn verify_proof(root_hash: Vec<u8>, key: &[u8], proof: Proof) -> TrieResult<Option<Vec<u8>>> {
+		let memdb = Rc::new(MemoryDB::new());
+		for node_encoded in proof.nodes.into_iter() {
+			let hash = hasher_digest(&node_encoded);
+
+			if root_hash.eq(&hash) || node_encoded.len() >= LENGTH {
+				memdb.insert(hash, node_encoded);
+			}
+		}
+		let trie = MerklePatriciaTrie::from(memdb, &root_hash).or(Err(TrieError::InvalidProof))?;
+
+		trie.get(key).or(Err(TrieError::InvalidProof))
+	}
+}
+
+impl MerklePatriciaTrie {
+	pub fn iter(&self) -> TrieIterator {
+		let mut nodes = Vec::new();
+		nodes.push((self.root.clone()).into());
+		TrieIterator {
+			trie: self,
+			nibble: Nibbles::from_raw(vec![], false),
+			nodes,
+		}
+	}
+
+	fn get_at(&self, n: Node, partial: &Nibbles) -> TrieResult<Option<Vec<u8>>> {
+		match n {
+			Node::Empty => Ok(None),
+			Node::Leaf(leaf) => {
+				let borrow_leaf = leaf.borrow();
+
+				if &borrow_leaf.key == partial {
+					Ok(Some(borrow_leaf.value.clone()))
+				} else {
+					Ok(None)
+				}
+			}
+			Node::Branch(branch) => {
+				let borrow_branch = branch.borrow();
+
+				if partial.is_empty() || partial.at(0) == 16 {
+					Ok(borrow_branch.value.clone())
+				} else {
+					let index = partial.at(0);
+					self.get_at(borrow_branch.children[index].clone(), &partial.offset(1))
+				}
+			}
+			Node::Extension(extension) => {
+				let extension = extension.borrow();
+
+				let prefix = &extension.prefix;
+				let match_len = partial.common_prefix(&prefix);
+				if match_len == prefix.len() {
+					self.get_at(extension.node.clone(), &partial.offset(match_len))
+				} else {
+					Ok(None)
+				}
+			}
+			Node::Hash(hash_node) => {
+				let borrow_hash_node = hash_node.borrow();
+				let n = self.recover_from_db(&borrow_hash_node.hash)?;
+				self.get_at(n, partial)
+			}
+		}
+	}
+
+	fn insert_at(&self, n: Node, partial: Nibbles, value: Vec<u8>) -> TrieResult<Node> {
+		match n {
+			Node::Empty => Ok(Node::from_leaf(partial, value)),
+			Node::Leaf(leaf) => {
+				let mut borrow_leaf = leaf.borrow_mut();
+
+				let old_partial = &borrow_leaf.key;
+				let match_index = partial.common_prefix(old_partial);
+				if match_index == old_partial.len() {
+					// replace leaf value
+					borrow_leaf.value = value;
+					return Ok(Node::Leaf(leaf.clone()));
+				}
+
+				let mut branch = BranchNode {
+					children: empty_children(),
+					value: None,
+				};
+
+				let n = Node::from_leaf(old_partial.offset(match_index + 1), borrow_leaf.value.clone());
+				branch.insert(old_partial.at(match_index), n);
+
+				let n = Node::from_leaf(partial.offset(match_index + 1), value);
+				branch.insert(partial.at(match_index), n);
+
+				if match_index == 0 {
+					return Ok(Node::Branch(Rc::new(RefCell::new(branch))));
+				}
+
+				// if include a common prefix
+				Ok(Node::from_extension(
+					partial.slice(0, match_index),
+					Node::Branch(Rc::new(RefCell::new(branch))),
+				))
+			}
+			Node::Branch(branch) => {
+				let mut borrow_branch = branch.borrow_mut();
+
+				if partial.at(0) == 0x10 {
+					borrow_branch.value = Some(value);
+					return Ok(Node::Branch(branch.clone()));
+				}
+
+				let child = borrow_branch.children[partial.at(0)].clone();
+				let new_child = self.insert_at(child, partial.offset(1), value)?;
+				borrow_branch.children[partial.at(0)] = new_child;
+				Ok(Node::Branch(branch.clone()))
+			}
+			Node::Extension(ext) => {
+				let mut borrow_ext = ext.borrow_mut();
+
+				let prefix = &borrow_ext.prefix;
+				let sub_node = borrow_ext.node.clone();
+				let match_index = partial.common_prefix(&prefix);
+
+				if match_index == 0 {
+					let mut branch = BranchNode {
+						children: empty_children(),
+						value: None,
+					};
+					branch.insert(
+						prefix.at(0),
+						if prefix.len() == 1 {
+							sub_node
+						} else {
+							Node::from_extension(prefix.offset(1), sub_node)
+						},
+					);
+					let node = Node::Branch(Rc::new(RefCell::new(branch)));
+
+					return self.insert_at(node, partial, value);
+				}
+
+				if match_index == prefix.len() {
+					let new_node = self.insert_at(sub_node, partial.offset(match_index), value)?;
+					return Ok(Node::from_extension(prefix.clone(), new_node));
+				}
+
+				let new_ext = Node::from_extension(prefix.offset(match_index), sub_node);
+				let new_node = self.insert_at(new_ext, partial.offset(match_index), value)?;
+				borrow_ext.prefix = prefix.slice(0, match_index);
+				borrow_ext.node = new_node;
+				Ok(Node::Extension(ext.clone()))
+			}
+			Node::Hash(hash_node) => {
+				let borrow_hash_node = hash_node.borrow();
+
+				self.passing_keys.borrow_mut().insert(borrow_hash_node.hash.to_vec());
+				let n = self.recover_from_db(&borrow_hash_node.hash)?;
+				self.insert_at(n, partial, value)
+			}
+		}
+	}
+
+	fn delete_at(&self, n: Node, partial: &Nibbles) -> TrieResult<(Node, bool)> {
+		let (new_n, deleted) = match n {
+			Node::Empty => Ok((Node::Empty, false)),
+			Node::Leaf(leaf) => {
+				let borrow_leaf = leaf.borrow();
+
+				if &borrow_leaf.key == partial {
+					return Ok((Node::Empty, true));
+				}
+				Ok((Node::Leaf(leaf.clone()), false))
+			}
+			Node::Branch(branch) => {
+				let mut borrow_branch = branch.borrow_mut();
+
+				if partial.at(0) == 0x10 {
+					borrow_branch.value = None;
+					return Ok((Node::Branch(branch.clone()), true));
+				}
+
+				let index = partial.at(0);
+				let node = borrow_branch.children[index].clone();
+
+				let (new_n, deleted) = self.delete_at(node, &partial.offset(1))?;
+				if deleted {
+					borrow_branch.children[index] = new_n;
+				}
+
+				Ok((Node::Branch(branch.clone()), deleted))
+			}
+			Node::Extension(ext) => {
+				let mut borrow_ext = ext.borrow_mut();
+
+				let prefix = &borrow_ext.prefix;
+				let match_len = partial.common_prefix(prefix);
+
+				if match_len == prefix.len() {
+					let (new_n, deleted) = self.delete_at(borrow_ext.node.clone(), &partial.offset(match_len))?;
+
+					if deleted {
+						borrow_ext.node = new_n;
+					}
+
+					Ok((Node::Extension(ext.clone()), deleted))
+				} else {
+					Ok((Node::Extension(ext.clone()), false))
+				}
+			}
+			Node::Hash(hash_node) => {
+				let hash = hash_node.borrow().hash.clone();
+				self.passing_keys.borrow_mut().insert(hash.clone());
+
+				let n = self.recover_from_db(&hash)?;
+				self.delete_at(n, partial)
+			}
+		}?;
+
+		if deleted {
+			Ok((self.degenerate(new_n)?, deleted))
+		} else {
+			Ok((new_n, deleted))
+		}
+	}
+
+	fn degenerate(&self, n: Node) -> TrieResult<Node> {
+		match n {
+			Node::Branch(branch) => {
+				let borrow_branch = branch.borrow();
+
+				let mut used_indexs = vec![];
+				for (index, node) in borrow_branch.children.iter().enumerate() {
+					match node {
+						Node::Empty => continue,
+						_ => used_indexs.push(index),
+					}
+				}
+
+				// if only a value node, transmute to leaf.
+				if used_indexs.is_empty() && borrow_branch.value.is_some() {
+					let key = Nibbles::from_raw([].to_vec(), true);
+					let value = borrow_branch.value.clone().unwrap();
+					Ok(Node::from_leaf(key, value))
+				// if only one node. make an extension.
+				} else if used_indexs.len() == 1 && borrow_branch.value.is_none() {
+					let used_index = used_indexs[0];
+					let n = borrow_branch.children[used_index].clone();
+
+					let new_node = Node::from_extension(Nibbles::from_hex(vec![used_index as u8]), n);
+					self.degenerate(new_node)
+				} else {
+					Ok(Node::Branch(branch.clone()))
+				}
+			}
+			Node::Extension(ext) => {
+				let borrow_ext = ext.borrow();
+
+				let prefix = &borrow_ext.prefix;
+				match borrow_ext.node.clone() {
+					Node::Extension(sub_ext) => {
+						let borrow_sub_ext = sub_ext.borrow();
+
+						let new_prefix = prefix.join(&borrow_sub_ext.prefix);
+						let new_n = Node::from_extension(new_prefix, borrow_sub_ext.node.clone());
+						self.degenerate(new_n)
+					}
+					Node::Leaf(leaf) => {
+						let borrow_leaf = leaf.borrow();
+
+						let new_prefix = prefix.join(&borrow_leaf.key);
+						Ok(Node::from_leaf(new_prefix, borrow_leaf.value.clone()))
+					}
+					// try again after recovering node from the db.
+					Node::Hash(hash_node) => {
+						let hash = hash_node.borrow().hash.clone();
+						self.passing_keys.borrow_mut().insert(hash.clone());
+
+						let new_node = self.recover_from_db(&hash)?;
+
+						let n = Node::from_extension(borrow_ext.prefix.clone(), new_node);
+						self.degenerate(n)
+					}
+					_ => Ok(Node::Extension(ext.clone())),
+				}
+			}
+			_ => Ok(n),
+		}
+	}
+
+	// Get nodes path along the key, only the nodes whose encode length is greater than
+	// hash length are added.
+	// For embedded nodes whose data are already contained in their parent node, we don't need to
+	// add them in the path.
+	// In the code below, we only add the nodes get by `get_node_from_hash`, because they contains
+	// all data stored in db, including nodes whose encoded data is less than hash length.
+	fn get_path_at(&self, n: Node, partial: &Nibbles) -> TrieResult<Vec<Node>> {
+		match n {
+			Node::Empty | Node::Leaf(_) => Ok(vec![]),
+			Node::Branch(branch) => {
+				let borrow_branch = branch.borrow();
+
+				if partial.is_empty() || partial.at(0) == 16 {
+					Ok(vec![])
+				} else {
+					let node = borrow_branch.children[partial.at(0)].clone();
+					self.get_path_at(node, &partial.offset(1))
+				}
+			}
+			Node::Extension(ext) => {
+				let borrow_ext = ext.borrow();
+
+				let prefix = &borrow_ext.prefix;
+				let match_len = partial.common_prefix(prefix);
+
+				if match_len == prefix.len() {
+					self.get_path_at(borrow_ext.node.clone(), &partial.offset(match_len))
+				} else {
+					Ok(vec![])
+				}
+			}
+			Node::Hash(hash_node) => {
+				let n = self.recover_from_db(&hash_node.borrow().hash.clone())?;
+				let mut rest = self.get_path_at(n.clone(), partial)?;
+				rest.push(n);
+				Ok(rest)
+			}
+		}
+	}
+
+	fn commit(&mut self) -> TrieResult<Vec<u8>> {
+		let encoded = self.encode_node(self.root.clone());
+		let root_hash = if encoded.len() < LENGTH {
+			let hash = hasher_digest(&encoded);
+			self.cache.borrow_mut().insert(hash.clone(), encoded);
+			hash
+		} else {
+			encoded
+		};
+
+		let mut keys = Vec::with_capacity(self.cache.borrow().len());
+		let mut values = Vec::with_capacity(self.cache.borrow().len());
+		for (k, v) in self.cache.borrow_mut().drain() {
+			keys.push(k.to_vec());
+			values.push(v);
+		}
+
+		self.db.insert_batch(keys, values);
+
+		let removed_keys: Vec<Vec<u8>> = self
+			.passing_keys
+			.borrow()
+			.iter()
+			.filter(|h| !self.gen_keys.borrow().contains(&h.to_vec()))
+			.map(|h| h.to_vec())
+			.collect();
+
+		self.db.remove_batch(&removed_keys);
+
+		self.root_hash = root_hash.to_vec();
+		self.gen_keys.borrow_mut().clear();
+		self.passing_keys.borrow_mut().clear();
+		self.root = self.recover_from_db(&root_hash)?;
+		Ok(root_hash)
+	}
+
+	fn encode_node(&self, n: Node) -> Vec<u8> {
+		// Returns the hash value directly to avoid double counting.
+		if let Node::Hash(hash_node) = n {
+			return hash_node.borrow().hash.clone();
+		}
+
+		let data = self.encode_raw(n.clone());
+		// Nodes smaller than 32 bytes are stored inside their parent,
+		// Nodes equal to 32 bytes are returned directly
+		if data.len() < LENGTH {
+			data
+		} else {
+			let hash = hasher_digest(&data);
+			self.cache.borrow_mut().insert(hash.clone(), data);
+
+			self.gen_keys.borrow_mut().insert(hash.clone());
+			hash
+		}
+	}
+
+	fn encode_raw(&self, n: Node) -> Vec<u8> {
+		match n {
+			Node::Empty => rlp::NULL_RLP.to_vec(),
+			Node::Leaf(leaf) => {
+				let borrow_leaf = leaf.borrow();
+
+				let mut stream = RlpStream::new_list(2);
+				stream.append(&borrow_leaf.key.encode_compact());
+				stream.append(&borrow_leaf.value);
+				stream.out()
+			}
+			Node::Branch(branch) => {
+				let borrow_branch = branch.borrow();
+
+				let mut stream = RlpStream::new_list(17);
+				for i in 0..16 {
+					let n = borrow_branch.children[i].clone();
+					let data = self.encode_node(n);
+					if data.len() == LENGTH {
+						stream.append(&data);
+					} else {
+						stream.append_raw(&data, 1);
+					}
+				}
+
+				match &borrow_branch.value {
+					Some(v) => stream.append(v),
+					None => stream.append_empty_data(),
+				};
+				stream.out()
+			}
+			Node::Extension(ext) => {
+				let borrow_ext = ext.borrow();
+
+				let mut stream = RlpStream::new_list(2);
+				stream.append(&borrow_ext.prefix.encode_compact());
+				let data = self.encode_node(borrow_ext.node.clone());
+				if data.len() == LENGTH {
+					stream.append(&data);
+				} else {
+					stream.append_raw(&data, 1);
+				}
+				stream.out()
+			}
+			Node::Hash(_hash) => unreachable!(),
+		}
+	}
+
+	fn decode_node(&self, data: &[u8]) -> TrieResult<Node> {
+		let r = Rlp::new(data);
+
+		match r.prototype()? {
+			Prototype::Data(0) => Ok(Node::Empty),
+			// extension node or leaf node
+			Prototype::List(2) => {
+				let key = r.at(0)?.data()?;
+				let key = Nibbles::from_compact(key.to_vec());
+
+				if key.is_leaf() {
+					Ok(Node::from_leaf(key, r.at(1)?.data()?.to_vec()))
+				} else {
+					let n = self.decode_node(r.at(1)?.as_raw())?;
+
+					Ok(Node::from_extension(key, n))
+				}
+			}
+			// branch node
+			Prototype::List(17) => {
+				let mut nodes = empty_children();
+				#[allow(clippy::needless_range_loop)]
+				for i in 0..nodes.len() {
+					let rlp_data = r.at(i)?;
+					let n = self.decode_node(rlp_data.as_raw())?;
+					nodes[i] = n;
+				}
+
+				// The last element is a value node.
+				let value_rlp = r.at(16)?;
+				let value = if value_rlp.is_empty() {
+					None
+				} else {
+					Some(value_rlp.data()?.to_vec())
+				};
+
+				Ok(Node::from_branch(nodes, value))
+			}
+			_ => {
+				if r.is_data() && r.size() == LENGTH {
+					Ok(Node::from_hash(r.data()?.to_vec()))
+				} else {
+					Err(TrieError::InvalidData)
+				}
+			}
+		}
+	}
+
+	fn recover_from_db(&self, key: &[u8]) -> TrieResult<Node> {
+		match self.db.get(key) {
+			Some(value) => Ok(self.decode_node(&value)?),
+			None => Ok(Node::Empty),
+		}
+	}
+}
+
+#[derive(Clone, Debug)]
+enum TraceStatus {
+	Start,
+	Doing,
+	Child(u8),
+	End,
+}
+
+#[derive(Clone, Debug)]
+struct TraceNode {
+	node: Node,
+	status: TraceStatus,
+}
+
+impl TraceNode {
+	fn advance(&mut self) {
+		self.status = match &self.status {
+			TraceStatus::Start => TraceStatus::Doing,
+			TraceStatus::Doing => match self.node {
+				Node::Branch(_) => TraceStatus::Child(0),
+				_ => TraceStatus::End,
+			},
+			TraceStatus::Child(i) if *i < 15 => TraceStatus::Child(i + 1),
+			_ => TraceStatus::End,
+		}
+	}
+}
+
+impl From<Node> for TraceNode {
+	fn from(node: Node) -> TraceNode {
+		TraceNode {
+			node,
+			status: TraceStatus::Start,
+		}
+	}
+}
+
+pub struct TrieIterator<'a> {
+	trie: &'a MerklePatriciaTrie,
+	nibble: Nibbles,
+	nodes: Vec<TraceNode>,
+}
+
+impl<'a> Iterator for TrieIterator<'a> {
+	type Item = (Vec<u8>, Vec<u8>);
+
+	fn next(&mut self) -> Option<Self::Item> {
+		loop {
+			let mut now = self.nodes.last().cloned();
+			if let Some(ref mut now) = now {
+				self.nodes.last_mut().unwrap().advance();
+
+				match (now.status.clone(), &now.node) {
+					(TraceStatus::End, node) => {
+						match *node {
+							Node::Leaf(ref leaf) => {
+								let cur_len = self.nibble.len();
+								self.nibble.truncate(cur_len - leaf.borrow().key.len());
+							}
+
+							Node::Extension(ref ext) => {
+								let cur_len = self.nibble.len();
+								self.nibble.truncate(cur_len - ext.borrow().prefix.len());
+							}
+
+							Node::Branch(_) => {
+								self.nibble.pop();
+							}
+							_ => {}
+						}
+						self.nodes.pop();
+					}
+
+					(TraceStatus::Doing, Node::Extension(ref ext)) => {
+						self.nibble.extend(&ext.borrow().prefix);
+						self.nodes.push((ext.borrow().node.clone()).into());
+					}
+
+					(TraceStatus::Doing, Node::Leaf(ref leaf)) => {
+						self.nibble.extend(&leaf.borrow().key);
+						return Some((self.nibble.encode_raw().0, leaf.borrow().value.clone()));
+					}
+
+					(TraceStatus::Doing, Node::Branch(ref branch)) => {
+						let value = branch.borrow().value.clone();
+						if value.is_none() {
+							continue;
+						} else {
+							return Some((self.nibble.encode_raw().0, value.unwrap()));
+						}
+					}
+
+					(TraceStatus::Doing, Node::Hash(ref hash_node)) => {
+						if let Ok(n) = self.trie.recover_from_db(&hash_node.borrow().hash.clone()) {
+							self.nodes.pop();
+							self.nodes.push(n.into());
+						} else {
+							//error!();
+							return None;
+						}
+					}
+
+					(TraceStatus::Child(i), Node::Branch(ref branch)) => {
+						if i == 0 {
+							self.nibble.push(0);
+						} else {
+							self.nibble.pop();
+							self.nibble.push(i);
+						}
+						self.nodes.push((branch.borrow().children[i as usize].clone()).into());
+					}
+
+					(_, Node::Empty) => {
+						self.nodes.pop();
+					}
+					_ => {}
+				}
+			} else {
+				return None;
+			}
+		}
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use rand::distributions::Alphanumeric;
+	use rand::seq::SliceRandom;
+	use rand::{thread_rng, Rng};
+	use std::collections::{HashMap, HashSet};
+	use std::rc::Rc;
+
+	use ethereum_types;
+
+	use super::*;
+	use crate::db::MemoryDB;
+	use core::borrow::Borrow;
+
+	#[test]
+	fn test_trie_insert() {
+		let memdb = Rc::new(MemoryDB::new());
+		let mut trie = MerklePatriciaTrie::new(memdb);
+		trie.insert(b"test".to_vec(), b"test".to_vec()).unwrap();
+	}
+
+	#[test]
+	fn test_trie_get() {
+		let memdb = Rc::new(MemoryDB::new());
+		let mut trie = MerklePatriciaTrie::new(memdb);
+		trie.insert(b"test".to_vec(), b"test".to_vec()).unwrap();
+		let v = trie.get(b"test").unwrap();
+
+		assert_eq!(Some(b"test".to_vec()), v)
+	}
+
+	#[test]
+	fn test_trie_random_insert() {
+		let memdb = Rc::new(MemoryDB::new());
+		let mut trie = MerklePatriciaTrie::new(memdb);
+
+		for _ in 0..1000 {
+			let rand_str: String = thread_rng().sample_iter(&Alphanumeric).take(30).collect();
+			let val = rand_str.as_bytes();
+			trie.insert(val.to_vec(), val.to_vec()).unwrap();
+
+			let v = trie.get(val).unwrap();
+			assert_eq!(v.map(|v| v.to_vec()), Some(val.to_vec()));
+		}
+	}
+
+	#[test]
+	fn test_trie_contains() {
+		let memdb = Rc::new(MemoryDB::new());
+		let mut trie = MerklePatriciaTrie::new(memdb);
+		trie.insert(b"test".to_vec(), b"test".to_vec()).unwrap();
+		assert_eq!(true, trie.contains(b"test").unwrap());
+		assert_eq!(false, trie.contains(b"test2").unwrap());
+	}
+
+	#[test]
+	fn test_trie_remove() {
+		let memdb = Rc::new(MemoryDB::new());
+		let mut trie = MerklePatriciaTrie::new(memdb);
+		trie.insert(b"test".to_vec(), b"test".to_vec()).unwrap();
+		let removed = trie.remove(b"test").unwrap();
+		assert_eq!(true, removed)
+	}
+
+	#[test]
+	fn test_trie_random_remove() {
+		let memdb = Rc::new(MemoryDB::new());
+		let mut trie = MerklePatriciaTrie::new(memdb);
+
+		for _ in 0..1000 {
+			let rand_str: String = thread_rng().sample_iter(&Alphanumeric).take(30).collect();
+			let val = rand_str.as_bytes();
+			trie.insert(val.to_vec(), val.to_vec()).unwrap();
+
+			let removed = trie.remove(val).unwrap();
+			assert_eq!(true, removed);
+		}
+	}
+
+	#[test]
+	fn test_trie_from_root() {
+		let memdb = Rc::new(MemoryDB::new());
+		let root = {
+			let mut trie = MerklePatriciaTrie::new(memdb.clone());
+			trie.insert(b"test".to_vec(), b"test".to_vec()).unwrap();
+			trie.insert(b"test1".to_vec(), b"test".to_vec()).unwrap();
+			trie.insert(b"test2".to_vec(), b"test".to_vec()).unwrap();
+			trie.insert(b"test23".to_vec(), b"test".to_vec()).unwrap();
+			trie.insert(b"test33".to_vec(), b"test".to_vec()).unwrap();
+			trie.insert(b"test44".to_vec(), b"test".to_vec()).unwrap();
+			trie.root().unwrap()
+		};
+
+		let mut trie = MerklePatriciaTrie::from(Rc::clone(&memdb), &root).unwrap();
+		let v1 = trie.get(b"test33").unwrap();
+		assert_eq!(Some(b"test".to_vec()), v1);
+		let v2 = trie.get(b"test44").unwrap();
+		assert_eq!(Some(b"test".to_vec()), v2);
+		let root2 = trie.root().unwrap();
+		assert_eq!(hex::encode(root), hex::encode(root2));
+	}
+
+	#[test]
+	fn test_trie_from_root_and_insert() {
+		let memdb = Rc::new(MemoryDB::new());
+		let root = {
+			let mut trie = MerklePatriciaTrie::new(memdb.clone());
+			trie.insert(b"test".to_vec(), b"test".to_vec()).unwrap();
+			trie.insert(b"test1".to_vec(), b"test".to_vec()).unwrap();
+			trie.insert(b"test2".to_vec(), b"test".to_vec()).unwrap();
+			trie.insert(b"test23".to_vec(), b"test".to_vec()).unwrap();
+			trie.insert(b"test33".to_vec(), b"test".to_vec()).unwrap();
+			trie.insert(b"test44".to_vec(), b"test".to_vec()).unwrap();
+			trie.commit().unwrap()
+		};
+
+		let mut trie = MerklePatriciaTrie::from(Rc::clone(&memdb), &root).unwrap();
+		trie.insert(b"test55".to_vec(), b"test55".to_vec()).unwrap();
+		trie.commit().unwrap();
+		let v = trie.get(b"test55").unwrap();
+		assert_eq!(Some(b"test55".to_vec()), v);
+	}
+
+	#[test]
+	fn test_trie_from_root_and_delete() {
+		let memdb = Rc::new(MemoryDB::new());
+		let root = {
+			let mut trie = MerklePatriciaTrie::new(memdb.clone());
+			trie.insert(b"test".to_vec(), b"test".to_vec()).unwrap();
+			trie.insert(b"test1".to_vec(), b"test".to_vec()).unwrap();
+			trie.insert(b"test2".to_vec(), b"test".to_vec()).unwrap();
+			trie.insert(b"test23".to_vec(), b"test".to_vec()).unwrap();
+			trie.insert(b"test33".to_vec(), b"test".to_vec()).unwrap();
+			trie.insert(b"test44".to_vec(), b"test".to_vec()).unwrap();
+			trie.commit().unwrap()
+		};
+
+		let mut trie = MerklePatriciaTrie::from(Rc::clone(&memdb), &root).unwrap();
+		let removed = trie.remove(b"test44").unwrap();
+		assert_eq!(true, removed);
+		let removed = trie.remove(b"test33").unwrap();
+		assert_eq!(true, removed);
+		let removed = trie.remove(b"test23").unwrap();
+		assert_eq!(true, removed);
+	}
+
+	#[test]
+	fn test_multiple_trie_roots() {
+		let k0: ethereum_types::H256 = 0.into();
+		let k1: ethereum_types::H256 = 1.into();
+		let v: ethereum_types::H256 = 0x1234.into();
+
+		let root1 = {
+			let memdb = Rc::new(MemoryDB::new());
+			let mut trie = MerklePatriciaTrie::new(memdb);
+			trie.insert(k0.as_bytes().to_vec(), v.as_bytes().to_vec()).unwrap();
+			trie.root().unwrap()
+		};
+
+		let root2 = {
+			let memdb = Rc::new(MemoryDB::new());
+			let mut trie = MerklePatriciaTrie::new(memdb);
+			trie.insert(k0.as_bytes().to_vec(), v.as_bytes().to_vec()).unwrap();
+			trie.insert(k1.as_bytes().to_vec(), v.as_bytes().to_vec()).unwrap();
+			trie.root().unwrap();
+			trie.remove(k1.as_ref()).unwrap();
+			trie.root().unwrap()
+		};
+
+		let root3 = {
+			let memdb = Rc::new(MemoryDB::new());
+			let mut trie1 = MerklePatriciaTrie::new(memdb.clone());
+			trie1.insert(k0.as_bytes().to_vec(), v.as_bytes().to_vec()).unwrap();
+			trie1.insert(k1.as_bytes().to_vec(), v.as_bytes().to_vec()).unwrap();
+			trie1.root().unwrap();
+			let root = trie1.root().unwrap();
+			let mut trie2 = MerklePatriciaTrie::from(Rc::clone(&memdb), &root).unwrap();
+			trie2.remove(&k1.as_bytes().to_vec()).unwrap();
+			trie2.root().unwrap()
+		};
+
+		assert_eq!(root1, root2);
+		assert_eq!(root2, root3);
+	}
+
+	#[test]
+	fn test_delete_stale_keys_with_random_insert_and_delete() {
+		let memdb = Rc::new(MemoryDB::new());
+		let mut trie = MerklePatriciaTrie::new(memdb);
+
+		let mut rng = rand::thread_rng();
+		let mut keys = vec![];
+		for _ in 0..100 {
+			let random_bytes: Vec<u8> = (0..rng.gen_range(2, 30)).map(|_| rand::random::<u8>()).collect();
+			trie.insert(random_bytes.clone(), random_bytes.clone()).unwrap();
+			keys.push(random_bytes.clone());
+		}
+		trie.commit().unwrap();
+		let slice = &mut keys;
+		slice.shuffle(&mut rng);
+
+		for key in slice.iter() {
+			trie.remove(key).unwrap();
+		}
+		trie.commit().unwrap();
+
+		println!("{:?}", trie);
+		let empty_node_key = hasher_digest(&rlp::NULL_RLP);
+		println!("empty key{:?}", empty_node_key);
+		let value = trie.db.get(empty_node_key.as_ref()).unwrap();
+		assert_eq!(value, &rlp::NULL_RLP)
+	}
+
+	#[test]
+	fn insert_full_branch() {
+		let memdb = Rc::new(MemoryDB::new());
+		let mut trie = MerklePatriciaTrie::new(memdb);
+
+		trie.insert(b"test".to_vec(), b"test".to_vec()).unwrap();
+		trie.insert(b"test1".to_vec(), b"test".to_vec()).unwrap();
+		trie.insert(b"test2".to_vec(), b"test".to_vec()).unwrap();
+		trie.insert(b"test23".to_vec(), b"test".to_vec()).unwrap();
+		trie.insert(b"test33".to_vec(), b"test".to_vec()).unwrap();
+		trie.insert(b"test44".to_vec(), b"test".to_vec()).unwrap();
+		trie.root().unwrap();
+
+		let v = trie.get(b"test").unwrap();
+		assert_eq!(Some(b"test".to_vec()), v);
+	}
+
+	#[test]
+	fn iterator_trie() {
+		let memdb = Rc::new(MemoryDB::new());
+		let mut root1;
+		let mut kv = HashMap::new();
+		kv.insert(b"test".to_vec(), b"test".to_vec());
+		kv.insert(b"test1".to_vec(), b"test1".to_vec());
+		kv.insert(b"test11".to_vec(), b"test2".to_vec());
+		kv.insert(b"test14".to_vec(), b"test3".to_vec());
+		kv.insert(b"test16".to_vec(), b"test4".to_vec());
+		kv.insert(b"test18".to_vec(), b"test5".to_vec());
+		kv.insert(b"test2".to_vec(), b"test6".to_vec());
+		kv.insert(b"test23".to_vec(), b"test7".to_vec());
+		kv.insert(b"test9".to_vec(), b"test8".to_vec());
+		{
+			let mut trie = MerklePatriciaTrie::new(memdb.clone());
+			let mut kv = kv.clone();
+			kv.iter().for_each(|(k, v)| {
+				trie.insert(k.clone(), v.clone()).unwrap();
+			});
+			root1 = trie.root().unwrap();
+
+			trie.iter().for_each(|(k, v)| assert_eq!(kv.remove(&k).unwrap(), v));
+			assert!(kv.is_empty());
+		}
+
+		{
+			let mut trie = MerklePatriciaTrie::new(Rc::clone(&memdb));
+			let mut kv2 = HashMap::new();
+			kv2.insert(b"test".to_vec(), b"test11".to_vec());
+			kv2.insert(b"test1".to_vec(), b"test12".to_vec());
+			kv2.insert(b"test14".to_vec(), b"test13".to_vec());
+			kv2.insert(b"test22".to_vec(), b"test14".to_vec());
+			kv2.insert(b"test9".to_vec(), b"test15".to_vec());
+			kv2.insert(b"test16".to_vec(), b"test16".to_vec());
+			kv2.insert(b"test2".to_vec(), b"test17".to_vec());
+			kv2.iter().for_each(|(k, v)| {
+				trie.insert(k.clone(), v.clone()).unwrap();
+			});
+
+			trie.root().unwrap();
+
+			let mut kv_delete = HashSet::new();
+			kv_delete.insert(b"test".to_vec());
+			kv_delete.insert(b"test1".to_vec());
+			kv_delete.insert(b"test14".to_vec());
+
+			kv_delete.iter().for_each(|k| {
+				trie.remove(&k).unwrap();
+			});
+
+			kv2.retain(|k, _| !kv_delete.contains(k));
+
+			trie.root().unwrap();
+			trie.iter().for_each(|(k, v)| assert_eq!(kv2.remove(&k).unwrap(), v));
+			assert!(kv2.is_empty());
+		}
+
+		let trie = MerklePatriciaTrie::from(Rc::clone(&memdb), &root1).unwrap();
+		trie.iter().for_each(|(k, v)| assert_eq!(kv.remove(&k).unwrap(), v));
+		assert!(kv.is_empty());
+	}
+}
diff --git a/core/sr-eth-primitives/Cargo.toml b/core/sr-eth-primitives/Cargo.toml
index 43020e065..2271bd211 100644
--- a/core/sr-eth-primitives/Cargo.toml
+++ b/core/sr-eth-primitives/Cargo.toml
@@ -37,10 +37,6 @@ std = [
     "rlp/std",
     "keccak-hash/std",
     "primitive-types/std",
-#    "primitive-types/serde",
-#    "primitive-types/byteorder",
-#    "primitive-types/rustc-hex",
-#    "primitive-types/libc",
     "ethereum-types/std",
     "impl-codec/std",
     "fixed-hash/std",
diff --git a/core/sr-eth-primitives/src/header.rs b/core/sr-eth-primitives/src/header.rs
index 13f351acb..36a14802a 100644
--- a/core/sr-eth-primitives/src/header.rs
+++ b/core/sr-eth-primitives/src/header.rs
@@ -1,6 +1,7 @@
 use super::*;
+
+use codec::{Decode, Encode};
 use ethbloom::Bloom;
-use pow::EthashSeal;
 use rlp::RlpStream;
 use sr_primitives::RuntimeDebug;
 
@@ -243,6 +244,54 @@ mod tests {
 		(header1, header2)
 	}
 
+	fn ropsten_sequential_header() -> (EthHeader, EthHeader) {
+		let mixh1 = H256::from(hex!("c4b28f4b671b2e675634f596840d3115ce3df0ab38b6608a69371da16a3455aa"));
+		let nonce1 = H64::from(hex!("7afbefa403b138fa"));
+		// #6890091
+		// https://api-ropsten.etherscan.io/api?module=proxy&action=eth_getBlockByNumber&tag=0x69226b&boolean=true&apikey=YourApiKeyToken
+		// https://jsoneditoronline.org/
+		let header1 = EthHeader {
+			parent_hash: H256::from(hex!("8a18726cacb45b078bfe6491510cfa2dd578a70be2a217f416253cf3e94adbd2")),
+			timestamp: 0x5de5246c,
+			number: 0x69226b,
+			author: Address::from(hex!("4ccfb3039b78d3938588157564c9ad559bafab94")),
+			transactions_root: H256::from(hex!("e3ab46e9eeb65fea6b0b1ffd07587f3ee7741b66f16a0b63a3b0c01900387833")),
+			uncles_hash: H256::from(hex!("1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347")),
+			extra_data: "d983010906846765746889676f312e31312e3133856c696e7578".from_hex().unwrap(),
+			state_root: H256::from(hex!("de1df18f7da776a86119d17373d252d3591b5a4270e14113701d27c852d25313")),
+			receipts_root: H256::from(hex!("9c9eb20b6f9176864630f84aa11f33969a355efa85b2eb1e386a5b1ea3599089")),
+			log_bloom: Bloom::from_str("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").unwrap(),
+			gas_used: 0x769975.into(),
+			gas_limit: 0x7a1200.into(),
+			difficulty: 0xf4009f4b_u64.into(),
+			seal: vec![rlp::encode(&mixh1), rlp::encode(&nonce1)],
+			hash: Some(H256::from(hex!("1dafbf6a9825241ea5dfa7c3a54781c0784428f2ef3b588748521f83209d3caa"))),
+		};
+
+		// # 6890092
+		let mixh2 = H256::from(hex!("5a85e328a8bb041a386ffb25db029b7f0df4665a8a55b331b30a576761404fa6"));
+		let nonce2 = H64::from(hex!("650ea83006bb108d"));
+		let header2 = EthHeader {
+			parent_hash: H256::from(hex!("1dafbf6a9825241ea5dfa7c3a54781c0784428f2ef3b588748521f83209d3caa")),
+			timestamp: 0x5de52488,
+			number: 0x69226c,
+			author: Address::from(hex!("4ccfb3039b78d3938588157564c9ad559bafab94")),
+			transactions_root: H256::from(hex!("cd2672df775af7bcb2b93a478666d500dee3d78e6970c71071dc79642db24719")),
+			uncles_hash: H256::from(hex!("1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347")),
+			extra_data: "d983010906846765746889676f312e31312e3133856c696e7578".from_hex().unwrap(),
+			state_root: H256::from(hex!("ee6ad25ad26e79004f15b8d423a9952859983ad740924fd13165d6e20953ff3e")),
+			receipts_root: H256::from(hex!("b2f020ce6615246a711bed61f2f485833943adb734d8e1cddd93d7ae8a641451")),
+			log_bloom: Bloom::from_str("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").unwrap(),
+			gas_used: 0x702566.into(),
+			gas_limit: 0x7a1200.into(),
+			difficulty: 0xf3c49f25_u64.into(),
+			seal: vec![rlp::encode(&mixh2), rlp::encode(&nonce2)],
+			hash: Some(H256::from(hex!("21fe7ebfb3639254a0867995f3d490e186576b42aeea8c60f8e3360c256f7974"))),
+		};
+
+		(header1, header2)
+	}
+
 	#[test]
 	fn can_do_proof_of_work_verification_fail() {
 		let mut header: EthHeader = EthHeader::default();
@@ -273,11 +322,26 @@ mod tests {
 	}
 
 	#[test]
-	fn can_calculate_difficulty() {
+	fn can_calculate_difficulty_ropsten() {
+		let (header1, header2) = ropsten_sequential_header();
+		let expected = U256::from_str("f3c49f25").unwrap();
+		let mut ethash_params = EthashPartial::ropsten_test();
+		//		ethash_params.set_difficulty_bomb_delays(0xc3500, 5000000);
+		assert_eq!(ethash_params.calculate_difficulty(&header2, &header1), expected);
+	}
+
+	#[test]
+	fn can_calculate_difficulty_production() {
 		let (header1, header2) = sequential_header();
 		let expected = U256::from_str("92c07e50de0b9").unwrap();
-		let mut ethash_params = EthashPartial::test();
-		ethash_params.set_difficulty_bomb_delays(0xc3500, 5000000);
+		let mut ethash_params = EthashPartial::production();
 		assert_eq!(ethash_params.calculate_difficulty(&header2, &header1), expected);
 	}
+
+	#[test]
+	fn can_verify_basic_difficulty_production() {
+		let header = sequential_header().0;
+		let ethash_params = EthashPartial::production();
+		assert_eq!(ethash_params.verify_block_basic(&header), Ok(()));
+	}
 }
diff --git a/core/sr-eth-primitives/src/lib.rs b/core/sr-eth-primitives/src/lib.rs
index 1244b9925..e5a0723ef 100644
--- a/core/sr-eth-primitives/src/lib.rs
+++ b/core/sr-eth-primitives/src/lib.rs
@@ -4,8 +4,6 @@
 #[macro_use]
 pub extern crate rlp_derive;
 
-use rstd::vec::Vec;
-
 pub mod encoded;
 pub mod error;
 pub mod header;
@@ -13,25 +11,12 @@ pub mod pow;
 pub mod receipt;
 //pub mod transaction;
 
-use codec::{Decode, Encode};
 pub use ethbloom::{Bloom, Input as BloomInput};
-use fixed_hash::construct_fixed_hash;
-use impl_codec::impl_fixed_hash_codec;
-use impl_rlp::impl_fixed_hash_rlp;
-
 pub use ethereum_types::H64;
 pub use primitive_types::{H160, H256, U128, U256, U512};
+
+use rstd::vec::Vec;
+
 pub type Bytes = Vec<u8>;
 pub type Address = H160;
 pub type BlockNumber = u64;
-
-#[derive(Default, Clone, Copy, Eq, PartialEq, Encode, Decode)]
-pub struct BestBlock {
-	height: BlockNumber, // enough for ethereum poa network (kovan)
-	hash: H256,
-	total_difficulty: U256,
-}
-
-//construct_fixed_hash! {pub struct H64(8);}
-//impl_fixed_hash_rlp!(H64, 8);
-//impl_fixed_hash_codec!(H64, 8);
diff --git a/core/sr-eth-primitives/src/pow.rs b/core/sr-eth-primitives/src/pow.rs
index c70282a26..502b2befd 100644
--- a/core/sr-eth-primitives/src/pow.rs
+++ b/core/sr-eth-primitives/src/pow.rs
@@ -60,25 +60,56 @@ impl EthashPartial {
 		}
 	}
 
-	/// TODO: to find out the exact params, only for testing.
-	#[cfg(feature = "std")]
-	pub fn test() -> Self {
+	pub fn production() -> Self {
 		EthashPartial {
 			minimum_difficulty: U256::from(131072_u128),
 			difficulty_bound_divisor: U256::from(0x0800),
-			difficulty_increment_divisor: 0x3C,
-			metropolis_difficulty_increment_divisor: 0x1E,
-			duration_limit: 0x3C,
-			homestead_transition: 0x30d40,
+			difficulty_increment_divisor: 10,
+			metropolis_difficulty_increment_divisor: 9,
+			duration_limit: 13,
+			homestead_transition: 1150000,
+			difficulty_hardfork_transition: u64::max_value(),
+			difficulty_hardfork_bound_divisor: U256::from(2048),
+			bomb_defuse_transition: u64::max_value(),
+			eip100b_transition: 4370000,
+			ecip1010_pause_transition: u64::max_value(),
+			ecip1010_continue_transition: u64::max_value(),
+			difficulty_bomb_delays: {
+				let mut m = BTreeMap::new();
+				m.insert(4370000, 3000000);
+				m.insert(7280000, 2000000);
+				m
+			},
+			expip2_transition: u64::max_value(),
+			expip2_duration_limit: 30,
+			progpow_transition: u64::max_value(),
+		}
+	}
+
+	/// TODO: to find out the exact ropsten params, only for testing.
+	#[cfg(feature = "std")]
+	pub fn ropsten_test() -> Self {
+		EthashPartial {
+			minimum_difficulty: U256::from(0x20000),
+			difficulty_bound_divisor: U256::from(0x0800),
+			difficulty_increment_divisor: 10,
+			metropolis_difficulty_increment_divisor: 9,
+			duration_limit: 0xd,
+			homestead_transition: 0x0,
 			difficulty_hardfork_transition: 0x59d9,
-			difficulty_hardfork_bound_divisor: U256::from(0x0200),
-			bomb_defuse_transition: 0x30d40,
-			eip100b_transition: 0xC3500,
-			ecip1010_pause_transition: 0x2dc6c0,
-			ecip1010_continue_transition: 0x4c4b40,
-			difficulty_bomb_delays: BTreeMap::<BlockNumber, BlockNumber>::default(),
-			expip2_transition: 0xc3500,
-			expip2_duration_limit: 0x1e,
+			difficulty_hardfork_bound_divisor: U256::from(0x0800),
+			bomb_defuse_transition: u64::max_value(),
+			eip100b_transition: 0x19f0a0,
+			ecip1010_pause_transition: u64::max_value(),
+			ecip1010_continue_transition: u64::max_value(),
+			difficulty_bomb_delays: {
+				let mut m = BTreeMap::new();
+				m.insert(0x19f0a0, 0x2dc6c0);
+				m.insert(0x408b70, 0x1e8480);
+				m
+			},
+			expip2_transition: u64::max_value(),
+			expip2_duration_limit: 30,
 			progpow_transition: u64::max_value(),
 		}
 	}
diff --git a/core/sr-eth-primitives/src/receipt.rs b/core/sr-eth-primitives/src/receipt.rs
index 6e309cd42..e34b2b807 100644
--- a/core/sr-eth-primitives/src/receipt.rs
+++ b/core/sr-eth-primitives/src/receipt.rs
@@ -7,7 +7,9 @@ use rstd::prelude::*;
 use codec::{Decode, Encode};
 use primitive_types::{H256, U256};
 
-#[derive(PartialEq, Eq, Clone, Encode, Decode)]
+use sr_primitives::RuntimeDebug;
+
+#[derive(PartialEq, Eq, Clone, Encode, Decode, RuntimeDebug)]
 pub enum TransactionOutcome {
 	/// Status and state root are unknown under EIP-98 rules.
 	Unknown,
@@ -17,7 +19,7 @@ pub enum TransactionOutcome {
 	StatusCode(u8),
 }
 
-#[derive(PartialEq, Eq, Clone, RlpEncodable, RlpDecodable, Encode, Decode)]
+#[derive(PartialEq, Eq, Clone, RlpEncodable, RlpDecodable, Encode, Decode, RuntimeDebug)]
 pub struct LogEntry {
 	/// The address of the contract executing at the point of the `LOG` operation.
 	pub address: Address,
@@ -39,7 +41,7 @@ impl LogEntry {
 	}
 }
 
-#[derive(PartialEq, Eq, Clone, Encode, Decode)]
+#[derive(PartialEq, Eq, Clone, Encode, Decode, RuntimeDebug)]
 pub struct Receipt {
 	/// The total gas used in the block following execution of the transaction.
 	pub gas_used: U256,
diff --git a/node/runtime/Cargo.toml b/node/runtime/Cargo.toml
index 3c6ec6709..645a32e2a 100644
--- a/node/runtime/Cargo.toml
+++ b/node/runtime/Cargo.toml
@@ -52,7 +52,7 @@ version = { package = "sr-version", git = "https://github.com/darwinia-network/s
 # darwinia
 balances = { package = "darwinia-balances", path = '../../srml/balances', default-features = false }
 darwinia-support = { path = "../../srml/support", default-features = false }
-ethereum-bridge = { package = "darwinia-ethereum-bridge", path = "../../srml/ethereum-bridge", default-features = false }
+eth-relay = { package = "darwinia-eth-relay", path = "../../srml/eth-relay", default-features = false }
 kton = { package = "darwinia-kton", path = '../../srml/kton', default-features = false }
 node-primitives = { path = "../primitives", default-features = false }
 staking = { package = "darwinia-staking", path = "../../srml/staking", default-features = false }
@@ -109,7 +109,7 @@ std = [
 	# darwinia
 	"balances/std",
 	"darwinia-support/std",
-	"ethereum-bridge/std",
+	"eth-relay/std",
 	"kton/std",
 	"node-primitives/std",
 	"staking/std",
diff --git a/node/runtime/src/lib.rs b/node/runtime/src/lib.rs
index 947cb5e71..212d4b226 100644
--- a/node/runtime/src/lib.rs
+++ b/node/runtime/src/lib.rs
@@ -381,11 +381,9 @@ impl staking::Trait for Runtime {
 	type SessionInterface = Self;
 }
 
-//impl ethereum_bridge::Trait for Runtime {
-//	type Event = Event;
-//	type Ring = Balances;
-//	type Hash = Hash;
-//}
+impl eth_relay::Trait for Runtime {
+	type Event = Event;
+}
 
 construct_runtime!(
 	pub enum Runtime where
@@ -419,7 +417,7 @@ construct_runtime!(
 		Sudo: sudo,
 		Utility: utility::{Module, Call, Event},
 		
-//		EthereumBridge: ethereum_bridge::{Storage, Module, Event<T>, Call},
+		EthRelay: eth_relay::{Storage, Module, Event<T>, Call},
 	}
 );
 
diff --git a/srml/ethereum-bridge/Cargo.toml b/srml/eth-relay/Cargo.toml
similarity index 83%
rename from srml/ethereum-bridge/Cargo.toml
rename to srml/eth-relay/Cargo.toml
index b9320c2af..5a3888434 100644
--- a/srml/ethereum-bridge/Cargo.toml
+++ b/srml/eth-relay/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
-name = "darwinia-ethereum-bridge"
+name = "darwinia-eth-relay"
 version = "0.2.0"
-authors = ["Xavier Lau <c.estlavie@icloud.com>"]
+authors = ["Darwinia Network <hello@darwinia.network>"]
 edition = "2018"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
@@ -15,11 +15,10 @@ system = { package = "srml-system",  git = "https://github.com/darwinia-network/
 sr-primitives = { git = "https://github.com/darwinia-network/substrate.git", branch = "darwinia-develop", default-features = false }
 support = { package = "srml-support", git = "https://github.com/darwinia-network/substrate.git", branch = "darwinia-develop", default-features = false }
 sr-eth-primitives = { path = "../../core/sr-eth-primitives", default-features = false }
-ethash = { git = "https://github.com/hammeWang/ethash-rs.git", rev = "70a4f078", default-features = false}
-#merkle-mountain-range = { path = "../../core/merkle-mountain-range", default-features = false }
 
-#web3 = {git = "https://github.com/ABMatrix/rust-web3.git", branch = "develop", default-features = false }
 rlp = { package = "rlp", git = "https://github.com/darwinia-network/parity-common.git", default-features = false}
+ethash = { git = "https://github.com/hammeWang/ethash-rs.git", rev = "70a4f078", default-features = false}
+merkle-patricia-trie = { path = "../../core/merkle-patricia-trie", default-features = false}
 
 [features]
 default = ["std"]
@@ -33,4 +32,6 @@ std = [
     "sr-eth-primitives/std",
     "ethash/std",
     "rlp/std",
+    "ethash/std",
+    "merkle-patricia-trie/std",
 ]
diff --git a/srml/eth-relay/src/lib.rs b/srml/eth-relay/src/lib.rs
new file mode 100644
index 000000000..9e3deefc8
--- /dev/null
+++ b/srml/eth-relay/src/lib.rs
@@ -0,0 +1,268 @@
+//!  prototype module for bridging in ethereum poa blockcahin
+
+#![recursion_limit = "128"]
+#![cfg_attr(not(feature = "std"), no_std)]
+
+// use blake2::Blake2b;
+use codec::{Decode, Encode};
+use rstd::vec::Vec;
+use sr_eth_primitives::{
+	header::EthHeader, pow::EthashPartial, pow::EthashSeal, receipt::Receipt, BlockNumber as EthBlockNumber, H160,
+	H256, H64, U128, U256, U512,
+};
+
+use ethash::{EthereumPatch, LightDAG};
+
+use support::{decl_event, decl_module, decl_storage, dispatch::Result, ensure, traits::Currency};
+
+use system::ensure_signed;
+
+use sr_primitives::RuntimeDebug;
+
+use rlp::{decode, encode};
+
+use merkle_patricia_trie::{trie::Trie, MerklePatriciaTrie, Proof};
+
+type DAG = LightDAG<EthereumPatch>;
+
+pub trait Trait: system::Trait {
+	type Event: From<Event<Self>> + Into<<Self as system::Trait>::Event>;
+}
+
+/// Familial details concerning a block
+#[derive(Default, Clone, Copy, Eq, PartialEq, Encode, Decode)]
+pub struct BlockDetails {
+	/// Block number
+	pub height: EthBlockNumber,
+	pub hash: H256,
+	/// Total difficulty of the block and all its parents
+	pub total_difficulty: U256,
+	//	/// Parent block hash
+	//	pub parent: H256,
+	//	/// List of children block hashes
+	//	pub children: Vec<H256>,
+	//	/// Whether the block is considered finalized
+	//	pub is_finalized: bool,
+}
+
+#[derive(PartialEq, Eq, Clone, Encode, Decode, RuntimeDebug)]
+pub struct ActionRecord {
+	pub index: u64,
+	pub proof: Vec<u8>,
+	pub header_hash: H256,
+}
+
+decl_storage! {
+	trait Store for Module<T: Trait> as EthRelay {
+		/// Anchor block that works as genesis block
+		pub BeginHeader get(fn begin_header): Option<EthHeader>;
+
+		/// Info of the best block header for now
+		pub BestHeaderHash get(fn best_header_hash): H256;
+
+		pub HeaderOf get(header_of): map H256 => Option<EthHeader>;
+
+		pub HeaderDetailsOf get(header_details_of): map H256 => Option<BlockDetails>;
+
+		/// Block delay for verify transaction
+		pub FinalizeNumber get(finalize_number): Option<u64>;
+
+		pub ActionOf get(action_of): map T::Hash => Option<ActionRecord>;
+
+
+//		pub BestHashOf get(best_hash_of): map u64 => Option<H256>;
+
+//		pub HashsOf get(hashs_of): map u64 => Vec<H256>;
+
+//		pub HeaderForIndex get(header_for_index): map H256 => Vec<(u64, T::Hash)>;
+	}
+	add_extra_genesis {
+		config(header): Option<Vec<u8>>;
+		build(|config| {
+			if let Some(h) = &config.header {
+				let header: EthHeader = rlp::decode(&h).expect("can't deserialize the header");
+
+				// TODO: initilize other parameters.
+				<Module<T>>::genesis_header(&header);
+			}
+		});
+	}
+}
+
+decl_module! {
+	pub struct Module<T: Trait> for enum Call
+	where
+		origin: T::Origin
+	{
+		fn deposit_event() = default;
+
+		pub fn test_relay_header(origin, header: EthHeader) {
+			let _relayer = ensure_signed(origin)?;
+
+			<Module<T>>::deposit_event(RawEvent::NewHeader(header));
+		}
+
+		pub fn relay_header(origin, header: EthHeader) {
+			let _relayer = ensure_signed(origin)?;
+			// 1. There must be a corresponding parent hash
+			// 2. Update best hash if the current block number is larger than current best block's number （Chain reorg）
+
+			Self::verify_header(&header)?;
+
+			let header_hash = header.hash();
+			let block_number = header.number();
+
+			HeaderOf::insert(header_hash, &header);
+
+			let prev_total_difficulty = Self::header_details_of(header.parent_hash()).unwrap().total_difficulty;
+
+			HeaderDetailsOf::insert(header_hash, BlockDetails {
+				height: block_number,
+				hash: header_hash,
+				total_difficulty: prev_total_difficulty + header.difficulty()
+			});
+
+			let best_header_hash = Self::best_header_hash();
+			let best_header = Self::header_of(best_header_hash).ok_or("Can not find best header.");
+			let best_header_details = Self::header_details_of(best_header_hash).unwrap();
+
+			// TODO: Check total difficulty and reorg if necessary.
+			if prev_total_difficulty + header.difficulty() > best_header_details.total_difficulty {
+				BestHeaderHash::mutate(|hash| {
+					*hash = header_hash;
+				});
+			}
+
+			<Module<T>>::deposit_event(RawEvent::NewHeader(header));
+		}
+
+		pub fn test_check_receipt(origin, receipt: Receipt, proof_record: ActionRecord) {
+			let _relayer = ensure_signed(origin)?;
+
+			<Module<T>>::deposit_event(RawEvent::RelayProof(proof_record));
+		}
+
+		pub fn check_receipt(origin, receipt: Receipt, proof_record: ActionRecord) {
+			let _relayer = ensure_signed(origin)?;
+
+			let header_hash = proof_record.header_hash;
+			if !HeaderOf::exists(header_hash) {
+				return Err("This block header does not exist.")
+			}
+
+			let header = HeaderOf::get(header_hash).unwrap();
+
+			let proof: Proof = rlp::decode(&proof_record.proof).unwrap();
+			let key = rlp::encode(&proof_record.index);
+
+			let value = MerklePatriciaTrie::verify_proof(header.receipts_root().0.to_vec(), &key, proof)
+				.unwrap();
+			assert!(value.is_some());
+
+			let receipt_encoded = rlp::encode(&receipt);
+
+			assert_eq!(value.unwrap(), receipt_encoded);
+			// confirm that the block hash is right
+			// get the receipt MPT trie root from the block header
+			// Using receipt MPT trie root to verify the proof and index etc.
+
+			<Module<T>>::deposit_event(RawEvent::RelayProof(proof_record));
+		}
+
+		// Assuming that there are at least one honest worker submiting headers
+		// This method may be merged together with relay_header
+		pub fn challenge_header(origin, header: EthHeader) {
+			// if header confirmed then return
+			// if header in unverified header then challenge
+		}
+	}
+}
+
+decl_event! {
+	pub enum Event<T>
+	where
+		<T as system::Trait>::AccountId
+	{
+		NewHeader(EthHeader),
+		RelayProof(ActionRecord),
+		TODO(AccountId),
+	}
+}
+
+impl<T: Trait> Module<T> {
+	// TOOD: what is the total difficulty for genesis/begin header
+	pub fn genesis_header(header: &EthHeader) {
+		let header_hash = header.hash();
+		//		let block_number = header.number();
+
+		HeaderOf::insert(header_hash, header);
+
+		// TODO: initialize the header details, including total difficulty.
+
+		// Initialize the the best hash.
+		BestHeaderHash::mutate(|hash| {
+			*hash = header_hash;
+		});
+
+		// Initialize the header.
+		BeginHeader::put(header.clone());
+	}
+
+	/// 1. proof of difficulty
+	/// 2. proof of pow (mixhash)
+	/// 3. challenge
+	fn verify_header(header: &EthHeader) -> Result {
+		// check parent hash,
+		let parent_hash = header.parent_hash();
+
+		let number = header.number();
+		ensure!(
+			number >= Self::begin_header().unwrap().number(),
+			"block nubmer is too small."
+		);
+
+		let prev_header = Self::header_of(parent_hash).unwrap();
+
+		ensure!((prev_header.number() + 1) == number, "Block number does not match.");
+
+		// check difficulty
+		let ethash_params = EthashPartial::production();
+		//		ethash_params.set_difficulty_bomb_delays(0xc3500, 5000000);
+		let result = ethash_params.verify_block_basic(header);
+		match result {
+			Ok(_) => (),
+			Err(e) => {
+				return Err("Block difficulty verification failed.");
+			}
+		};
+
+		// verify difficulty
+		let difficulty = ethash_params.calculate_difficulty(header, &prev_header);
+		ensure!(difficulty == *header.difficulty(), "difficulty verification failed");
+
+		// verify mixhash
+		let seal = match EthashSeal::parse_seal(header.seal()) {
+			Err(e) => {
+				return Err("Seal parse error.");
+			}
+			Ok(x) => x,
+		};
+
+		let light_dag = DAG::new(number.into());
+		let partial_header_hash = header.bare_hash();
+		let mix_hash = light_dag.hashimoto(partial_header_hash, seal.nonce).0;
+
+		if mix_hash != seal.mix_hash {
+			return Err("Mixhash does not match.");
+		}
+
+		//			ensure!(best_header.height == block_number, "Block height does not match.");
+		//			ensure!(best_header.hash == *header.parent_hash(), "Block hash does not match.");
+
+		Ok(())
+	}
+
+	fn _punish(_who: &T::AccountId) -> Result {
+		unimplemented!()
+	}
+}
diff --git a/srml/ethereum-bridge/src/lib.rs b/srml/ethereum-bridge/src/lib.rs
deleted file mode 100644
index c3ece7c46..000000000
--- a/srml/ethereum-bridge/src/lib.rs
+++ /dev/null
@@ -1,157 +0,0 @@
-//!  prototype module for bridging in ethereum poa blockcahin
-
-#![recursion_limit = "128"]
-#![cfg_attr(not(feature = "std"), no_std)]
-
-// use blake2::Blake2b;
-use codec::{Decode, Encode};
-use rstd::vec::Vec;
-use sr_eth_primitives::{
-	header::EthHeader, pow::EthashPartial, BestBlock, BlockNumber as EthBlockNumber, H160, H256, H64, U128, U256, U512,
-};
-
-use ethash::{EthereumPatch, LightDAG};
-use support::{decl_event, decl_module, decl_storage, dispatch::Result, ensure, traits::Currency};
-use system::ensure_signed;
-
-use sr_primitives::RuntimeDebug;
-
-use rlp::{decode, encode};
-
-type DAG = LightDAG<EthereumPatch>;
-
-pub trait Trait: system::Trait {
-	type Event: From<Event<Self>> + Into<<Self as system::Trait>::Event>;
-	//	type Hash: rstd::hash::Hash;
-}
-
-#[derive(PartialEq, Eq, Clone, Encode, Decode, RuntimeDebug)]
-pub struct Proof {
-	pub nodes: Vec<Vec<u8>>,
-}
-
-#[derive(PartialEq, Eq, Clone, Encode, Decode, RuntimeDebug)]
-pub struct ActionRecord {
-	pub index: u64,
-	pub proof: Vec<u8>,
-	pub header_hash: H256,
-}
-
-decl_storage! {
-	trait Store for Module<T: Trait> as EthBridge {
-		/// Anchor block that works as genesis block
-		pub BeginHeader get(fn begin_header): Option<EthHeader>;
-		/// Info of the best block header for now
-		pub BestHeader get(fn best_header): BestBlock;
-		///
-		pub BlockList get(fn block_list): map EthBlockNumber => Option<EthHeader>;
-		/// nonce of each block
-		pub Nonce get(fn nonce): map EthBlockNumber => Option<H64>;
-
-		pub HeaderOf get(header_of): map H256 => Option<EthHeader>;
-
-//		pub BestHashOf get(best_hash_of): map u64 => Option<H256>;
-//		pub HashsOf get(hashs_of): map u64 => Vec<H256>;
-
-		/// Block delay for verify transaction
-		pub FinalizeNumber get(finalize_number): Option<u64>;
-
-		pub ActionOf get(action_of): map T::Hash => Option<ActionRecord>;
-
-		pub HeaderForIndex get(header_for_index): map H256 => Vec<(u64, T::Hash)>;
-	}
-	add_extra_genesis {
-		config(header): Option<Vec<u8>>;
-		build(|config| {
-			if let Some(h) = &config.header {
-				let header: EthHeader = rlp::decode(&h).expect("can't deserialize the header");
-				BeginHeader::put(header.clone());
-
-				<Module<T>>::genesis_header(header);
-			} else {
-//				BeginNumber::put(config.number);
-			}
-		});
-	}
-}
-
-decl_module! {
-	pub struct Module<T: Trait> for enum Call
-	where
-		origin: T::Origin
-	{
-		fn deposit_event() = default;
-
-		pub fn store_block_header(origin, header: EthHeader) {
-			let _relayer = ensure_signed(origin)?;
-//			let _ = Self::verify(&header)?;
-
-			<Module<T>>::deposit_event(RawEvent::NewHeader(header));
-		}
-
-		pub fn relay_receipt(origin, proof: ActionRecord) {
-			// confirm that the block hash is right
-			// get the receipt MPT trie root from the block header
-			// Using receipt MPT trie root to verify the proof and index etc.
-
-			let _relayer = ensure_signed(origin)?;
-
-			<Module<T>>::deposit_event(RawEvent::RelayProof(proof));
-		}
-
-		pub fn submit_header(origin, header: EthHeader) {
-			// if header confirmed then return
-			// if header in unverified header then challenge
-		}
-	}
-}
-
-decl_event! {
-	pub enum Event<T>
-	where
-		<T as system::Trait>::AccountId
-	{
-		NewHeader(EthHeader),
-		RelayProof(ActionRecord),
-		TODO(AccountId),
-	}
-}
-
-impl<T: Trait> Module<T> {
-	pub fn genesis_header(header: EthHeader) {
-		unimplemented!()
-	}
-
-	pub fn adjust_deposit_value() {
-		unimplemented!()
-	}
-
-	/// 1. proof of difficulty
-	/// 2. proof of pow (mixhash)
-	/// 3. challenge
-	fn verify(header: &EthHeader, nonce: H64) -> Result {
-		let number = header.number();
-		ensure!(
-			number >= Self::begin_header().unwrap().number(),
-			"block nubmer is too small."
-		);
-		let prev_header = Self::block_list(number - 1).ok_or("import ancestor block first.");
-
-		let mut ethash_params = EthashPartial::expanse();
-		ethash_params.set_difficulty_bomb_delays(0xc3500, 5000000);
-		// verify difficulty
-		//		let difficulty = ethash_params.calculate_difficulty(header, &prev_header);
-		//		ensure!(difficulty == header.difficulty(), "difficulty verification failed");
-
-		// verify mixhash
-		let light_dag = DAG::new(number.into());
-		let partial_header_hash = header.bare_hash();
-		let mix_hash = light_dag.hashimoto(partial_header_hash, nonce);
-
-		Ok(())
-	}
-
-	fn _punish(_who: &T::AccountId) -> Result {
-		unimplemented!()
-	}
-}
diff --git a/types.json b/types.json
index 85b4e0b5f..8a395f06b 100644
--- a/types.json
+++ b/types.json
@@ -2,10 +2,11 @@
 	"EpochDuration": "u64",
 	"EraIndex": "u32",
 	"TimeStamp": "u64",
-
     "RingBalanceOf": "u128",
 	"KtonBalanceOf": "u128",
 	"ExtendedBalance": "u128",
+	"Address": "H160",
+	"EthBlockNumber": "u64",
 	"StakingBalance": {
 		"_enum": {
 			"Ring": "RingBalanceOf",
@@ -62,5 +63,40 @@
 	"StakingLock": {
 		"staking_amount": "u128",
 		"unbondings": "Vec<NormalLock>"
+	},
+	"EthHeader": {
+		"parent_hash": "H256",
+		"timestamp": "u64",
+		"number": "EthBlockNumber",
+		"auth": "Address",
+		"transaction_root": "H256",
+		"uncles_hash": "H256",
+		"extra_data": "Bytes",
+		"state_root": "H256",
+		"receipts_root": "H256",
+		"log_bloom": "Bloom",
+		"gas_used": "U256",
+		"gas_limit": "U256",
+		"difficulty": "U256",
+		"seal": "Vec<Bytes>",
+		"hash": "Option<H256>"
+	},
+	"ActionRecord": {
+		"index": "u64",
+		"proof": "Vec<u8>",
+		"header_hash": "H256"
+	},
+	"BestBlock": {
+		"height": "EthBlockNumber",
+		"hash": "H256",
+		"total_difficulty": "U256"
+	},
+	"H64": {
+		"_struct": "[u8; 8]"
+	},
+	"BlockDetails": {
+		"height": "EthBlockNumber",
+		"hash": "H256",
+		"total_difficulty": "U256"
 	}
 }
\ No newline at end of file