SNIP-52 notification package + HKDF crypto funcs

Cargo.toml

@@ -34,6 +34,7 @@ snip721 = ["secret-toolkit-snip721", "utils"]
 storage = ["secret-toolkit-storage", "serialization"]
 utils = ["secret-toolkit-utils"]
 viewing-key = ["secret-toolkit-viewing-key"]
+notification = ["secret-toolkit-notification"]
 
 [dependencies]
 secret-toolkit-crypto = { version = "0.10.1", path = "packages/crypto", optional = true }
@@ -45,7 +46,7 @@ secret-toolkit-snip721 = { version = "0.10.1", path = "packages/snip721", option
 secret-toolkit-storage = { version = "0.10.1", path = "packages/storage", optional = true }
 secret-toolkit-utils = { version = "0.10.1", path = "packages/utils", optional = true }
 secret-toolkit-viewing-key = { version = "0.10.1", path = "packages/viewing_key", optional = true }
-
+secret-toolkit-notification = { version = "0.10.1", path = "packages/notification", optional = true }
 
 [workspace]
 members = ["packages/*"]

packages/crypto/Cargo.toml

@@ -18,6 +18,7 @@ default = ["hash", "ecc-secp256k1", "rand"]
 hash = ["sha2"]
 ecc-secp256k1 = ["secp256k1"]
 rand = ["hash", "rand_chacha", "rand_core"]
+hkdf = ["sha2"]
 
 [dependencies]
 rand_core = { version = "0.6.4", default-features = false, optional = true }
@@ -26,6 +27,7 @@ sha2 = { version = "0.10.6", default-features = false, optional = true }
 secp256k1 = { version = "0.27.0", default-features = false, features = [
     "alloc",
 ], optional = true }
+hkdf = "0.12.3"
 cosmwasm-std = { workspace = true }
 cc = { version = "=1.1.10" }
 

packages/crypto/src/hkdf.rs

@@ -0,0 +1,40 @@
+use cosmwasm_std::{StdError, StdResult};
+use hkdf::{hmac::Hmac, Hkdf};
+use sha2::{Sha256, Sha512};
+
+// Create alias for HMAC-SHA256
+pub type HmacSha256 = Hmac<Sha256>;
+
+pub fn hkdf_sha_256(
+    salt: &Option<Vec<u8>>,
+    ikm: &[u8],
+    info: &[u8],
+    length: usize,
+) -> StdResult<Vec<u8>> {
+    let hk: Hkdf<Sha256> = Hkdf::<Sha256>::new(salt.as_deref(), ikm);
+    let mut zero_bytes = vec![0u8; length];
+    let okm = zero_bytes.as_mut_slice();
+    match hk.expand(info, okm) {
+        Ok(_) => Ok(okm.to_vec()),
+        Err(e) => {
+            Err(StdError::generic_err(format!("{:?}", e)))
+        }
+    }
+}
+
+pub fn hkdf_sha_512(
+    salt: &Option<Vec<u8>>,
+    ikm: &[u8],
+    info: &[u8],
+    length: usize,
+) -> StdResult<Vec<u8>> {
+    let hk: Hkdf<Sha512> = Hkdf::<Sha512>::new(salt.as_deref(), ikm);
+    let mut zero_bytes = vec![0u8; length];
+    let okm = zero_bytes.as_mut_slice();
+    match hk.expand(info, okm) {
+        Ok(_) => Ok(okm.to_vec()),
+        Err(e) => {
+            Err(StdError::generic_err(format!("{:?}", e)))
+        }
+    }
+}

packages/crypto/src/lib.rs

@@ -12,3 +12,8 @@ pub use hash::{sha_256, SHA256_HASH_SIZE};
 
 #[cfg(feature = "rand")]
 pub use rng::ContractPrng;
+
+#[cfg(feature = "hkdf")]
+pub mod hkdf;
+#[cfg(feature = "hkdf")]
+pub use crate::hkdf::*;

packages/notification/Cargo.toml

@@ -0,0 +1,35 @@
+[package]
+name = "secret-toolkit-notification"
+version = "0.10.1"
+edition = "2021"
+authors = ["darwinzer0","blake-regalia"]
+license-file = "../../LICENSE"
+repository = "https://github.com/scrtlabs/secret-toolkit"
+readme = "Readme.md"
+description = "Helper tools for SNIP-52 notifications in Secret Contracts"
+categories = ["cryptography::cryptocurrencies", "wasm"]
+keywords = ["secret-network", "secret-contracts", "secret-toolkit"]
+
+[package.metadata.docs.rs]
+all-features = true
+
+[dependencies]
+cosmwasm-std = { workspace = true, version = "1.0.0" }
+serde = { workspace = true }
+
+ripemd = { version = "0.1.3", default-features = false }
+schemars = { workspace = true }
+
+# rand_core = { version = "0.6.4", default-features = false }
+# rand_chacha = { version = "0.3.1", default-features = false }
+sha2 = "0.10.6"
+chacha20poly1305 = { version = "0.10.1", default-features = false, features = ["alloc", "rand_core"] }
+generic-array = "0.14.7"
+hkdf = "0.12.3"
+primitive-types = { version = "0.12.2", default-features = false }
+hex = "0.4.3"
+minicbor = "0.25.1"
+
+secret-toolkit-crypto = { version = "0.10.1", path = "../crypto", features = [
+    "hash", "hkdf"
+] }

packages/notification/Readme.md

@@ -0,0 +1,72 @@
+# Secret Contract Development Toolkit - SNIP52 (Private Push Notification) Interface
+
+⚠️ This package is a sub-package of the `secret-toolkit` package. Please see its crate page for more context.
+
+These functions are meant to help you easily create notification channels for private push notifications in secret contracts (see [SNIP-52 Private Push Notification](https://github.com/SolarRepublic/SNIPs/blob/feat/snip-52/SNIP-52.md)).
+
+### Implementing a `DirectChannel` struct
+
+Each notification channel will have a specified data format, which is defined by creating a struct that implements the `DirectChannel` trait, which has one method: `encode_cbor`. 
+
+The following example illustrates how you might implement this for a channel called `my_channel` and notification data containing two fields: `sender` and `amount`.
+
+```rust
+use cosmwasm_std::{Api, StdError, StdResult};
+use secret_toolkit::notification::{EncoderExt, CBL_ARRAY_SHORT, CBL_BIGNUM_U64, CBL_U8, Notification, DirectChannel, GroupChannel};
+use serde::{Deserialize, Serialize};
+use minicbor_ser as cbor;
+
+#[derive(Serialize, Debug, Deserialize, Clone)]
+pub struct MyNotification {
+    pub sender: Addr,
+    pub amount: u128,
+}
+
+impl DirectChannel for MyNotification {
+    const CHANNEL_ID: &'static str = "my_channel";
+    const CDDL_SCHEMA: &'static str = "my_channel=[sender:bstr .size 20,amount:uint .size 8]";
+    const ELEMENTS: u64 = 2;
+    const PAYLOAD_SIZE: usize = CBL_ARRAY_SHORT + CBL_BIGNUM_U64 + CBL_U8;
+
+    fn encode_cbor(&self, api: &dyn Api, encoder: &mut Encoder<&mut [u8]>) -> StdResult<()> {
+        // amount:biguint (8-byte uint)
+        encoder.ext_u64_from_u128(self.amount)?;
+
+        // sender:bstr (20-byte address)
+        let sender_raw = api.addr_canonicalize(sender.as_str())?;
+        encoder.ext_address(sender_raw)?;
+
+        Ok(())
+    }
+}
+```
+
+
+### Sending a TxHash notification
+
+To send a notification to a recipient you first create a new `Notification` struct passing in the address of the recipient along with the notification data you want to send. Then to turn it into a `TxHashNotification` execute the `to_txhash_notification` method on the `Notification` by passing in `deps.api`, `env`, and an internal `secret`, which is a randomly generated byte slice that has been stored previously in your contract during initialization.
+
+The following code snippet creates a notification for the above `my_channel` and adds it to the contract `Response` as a plaintext attribute.
+
+```rust
+let notification = Notification::new(
+    recipient,
+    MyNotification {
+        sender,
+        1000_u128,
+    }
+)
+.to_txhash_notification(deps.api, &env, secret)?;
+
+// ... other code
+
+// add notification to response
+Ok(Response::new()
+    .set_data(to_binary(&ExecuteAnswer::MyMessage { status: Success } )?)
+    .add_attribute_plaintext(
+        notification.id_plaintext(),
+        notification.data_plaintext(),
+    )
+)
+```
+

packages/notification/src/cbor.rs

@@ -0,0 +1,102 @@
+use cosmwasm_std::{CanonicalAddr, StdResult, StdError};
+use minicbor::{data as cbor_data, encode as cbor_encode, Encoder};
+
+/// Length of encoding an arry header that holds less than 24 items
+pub const CBL_ARRAY_SHORT: usize = 1;
+
+/// Length of encoding an arry header that holds between 24 and 255 items
+pub const CBL_ARRAY_MEDIUM: usize = 2;
+
+/// Length of encoding an arry header that holds more than 255 items
+pub const CBL_ARRAY_LARGE: usize = 3;
+
+/// Length of encoding a u8 value that is less than 24
+pub const CBL_U8_LESS_THAN_24: usize = 1;
+
+/// Length of encoding a u8 value that is greater than or equal to 24
+pub const CBL_U8: usize = 1 + 1;
+
+/// Length of encoding a u16 value
+pub const CBL_U16: usize = 1 + 2;
+
+/// Length of encoding a u32 value
+pub const CBL_U32: usize = 1 + 4;
+
+/// Length of encoding a u53 value (the maximum safe integer size for javascript)
+pub const CBL_U53: usize = 1 + 8;
+
+/// Length of encoding a u64 value (with the bignum tag attached)
+pub const CBL_BIGNUM_U64: usize = 1 + 1 + 8;
+
+// Length of encoding a timestamp
+pub const CBL_TIMESTAMP: usize = 1 + 1 + 8;
+
+// Length of encoding a 20-byte canonical address
+pub const CBL_ADDRESS: usize = 1 + 20;
+
+/// Wraps the CBOR error to CosmWasm StdError
+pub fn cbor_to_std_error<T>(e: cbor_encode::Error<T>) -> StdError {
+	StdError::generic_err("CBOR encoding error")
+}
+
+/// Extends the minicbor encoder with wrapper functions that handle CBOR errors
+pub trait EncoderExt {
+	fn ext_tag(&mut self, tag: cbor_data::IanaTag) -> StdResult<&mut Self>;
+
+	fn ext_u8(&mut self, value: u8) -> StdResult<&mut Self>;
+	fn ext_u32(&mut self, value: u32) -> StdResult<&mut Self>;
+	fn ext_u64_from_u128(&mut self, value: u128) -> StdResult<&mut Self>;
+	fn ext_address(&mut self, value: CanonicalAddr) -> StdResult<&mut Self>;
+	fn ext_bytes(&mut self, value: &[u8]) -> StdResult<&mut Self>;
+	fn ext_timestamp(&mut self, value: u64) -> StdResult<&mut Self>;
+}
+
+impl<T: cbor_encode::Write> EncoderExt for Encoder<T> {
+	#[inline]
+	fn ext_tag(&mut self, tag: cbor_data::IanaTag) -> StdResult<&mut Self> {
+		 self
+			  .tag(cbor_data::Tag::from(tag))
+					.map_err(cbor_to_std_error)
+	}
+
+	#[inline]
+	fn ext_u8(&mut self, value: u8) -> StdResult<&mut Self> {
+		 self
+			  .u8(value)
+					.map_err(cbor_to_std_error)
+	}
+
+	#[inline]
+	fn ext_u32(&mut self, value: u32) -> StdResult<&mut Self> {
+		 self
+			  .u32(value)
+					.map_err(cbor_to_std_error)
+	}
+
+	#[inline]
+	fn ext_u64_from_u128(&mut self, value: u128) -> StdResult<&mut Self> {
+		 self
+			  .ext_tag(cbor_data::IanaTag::PosBignum)?
+			  .ext_bytes(&value.to_be_bytes()[8..])
+	}
+
+	#[inline]
+	fn ext_address(&mut self, value: CanonicalAddr) -> StdResult<&mut Self> {
+		 self.ext_bytes(&value.as_slice())
+	}
+
+	#[inline]
+	fn ext_bytes(&mut self, value: &[u8]) -> StdResult<&mut Self> {
+		 self
+			  .bytes(&value)
+					.map_err(cbor_to_std_error)
+	}
+
+	#[inline]
+	fn ext_timestamp(&mut self, value: u64) -> StdResult<&mut Self> {
+		 self
+			  .ext_tag(cbor_data::IanaTag::Timestamp)?
+			  .u64(value)
+					.map_err(cbor_to_std_error)
+	}
+}

packages/notification/src/cipher.rs

@@ -0,0 +1,20 @@
+use chacha20poly1305::{
+    aead::{AeadInPlace, KeyInit},
+    ChaCha20Poly1305,
+};
+use cosmwasm_std::{StdError, StdResult};
+use generic_array::GenericArray;
+
+pub fn cipher_data(key: &[u8], nonce: &[u8], plaintext: &[u8], aad: &[u8]) -> StdResult<Vec<u8>> {
+    let cipher = ChaCha20Poly1305::new_from_slice(key)
+        .map_err(|e| StdError::generic_err(format!("{:?}", e)))?;
+    let mut buffer: Vec<u8> = plaintext.to_vec();
+    cipher
+        .encrypt_in_place(GenericArray::from_slice(nonce), aad, &mut buffer)
+        .map_err(|e| StdError::generic_err(format!("{:?}", e)))?;
+    Ok(buffer)
+}
+
+pub fn xor_bytes(vec1: &[u8], vec2: &[u8]) -> Vec<u8> {
+    vec1.iter().zip(vec2.iter()).map(|(&a, &b)| a ^ b).collect()
+}