chore: DIP improvements (#602)

Fixes KILTprotocol/ticket#3054.

It also contains a **breaking change** for cross-chain DID signature
verifications. The signature now has a `valid_until` field, as discussed
in
#494 (comment).

Besides that, other changes include:

* A new set of types representing different stages of a cross-chain DIP
proof, during the verification process. Everything starts with either a
`RelayDipDidProof` or a `ParachainDipDidProof` and ends, if the whole
verification flow succeeds, with a `DipVerifiedInfo`.
* A generic `verify_storage_value_proof` that is used to verify a single
storage element with a storage proof.
* The `KiltVersionedParachainVerifier` now also depends on the
relaychain runtime, which removes the need for some traits that provided
just type definitions, such as `RelayChainStorageInfo` and
`RelayChainStateInfo`.
* Errors conversions into `u8` now start from `1` instead of `0`, for
disambiguating between an error returning `u8::MAX` and another case
returning `u8::MAX + 0`.
* Refactoring of the different modules.

**No unit tests or benchmarks yet, but this code should make it easier
to do all of those**.

crates/kilt-dip-primitives/Cargo.toml

@@ -39,15 +39,8 @@ sp-state-machine.workspace = true
 sp-std.workspace = true
 sp-trie.workspace = true
 
-# Polkadot dependencies
-rococo-runtime.workspace = true
-xcm.workspace = true
-xcm-executor.workspace = true
-
 # Cumulus dependencies
-cumulus-pallet-parachain-system.workspace = true
 cumulus-primitives-core.workspace = true
-parachain-info.workspace = true
 
 [dev-dependencies]
 hex-literal.workspace = true
@@ -75,16 +68,10 @@ std = [
   "sp-state-machine/std",
   "sp-std/std",
   "sp-trie/std",
-  "rococo-runtime/std",
-  "xcm/std",
-  "xcm-executor/std",
-  "cumulus-pallet-parachain-system/std",
   "cumulus-primitives-core/std",
-  "parachain-info/std",
 ]
 runtime-benchmarks = [
   "kilt-support/runtime-benchmarks",
   "pallet-dip-consumer/runtime-benchmarks",
   "pallet-dip-provider/runtime-benchmarks",
-  "rococo-runtime/runtime-benchmarks"
 ]

crates/kilt-dip-primitives/src/lib.rs

@@ -26,14 +26,18 @@
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
-pub mod did;
+/// Module to deal with cross-chain Merkle proof as generated by the KILT chain.
 pub mod merkle;
+/// Module to deal with cross-chain state proofs.
 pub mod state_proofs;
+/// Collection of traits used throughout the crate and useful for both providers
+/// and consumers.
 pub mod traits;
 pub mod utils;
+/// Verifier module containing types that implement the verifier component to be
+/// deployed both on a sibling parachain and on a parent relaychain.
 pub mod verifier;
 
-pub use state_proofs::relaychain::RelayStateRootsViaRelayStorePallet;
-pub use traits::{FrameSystemDidSignatureContext, ProviderParachainStateInfoViaProviderPallet};
-pub use utils::BoundedBlindedValue;
+pub use merkle::latest::*;
+pub use traits::RelayStateRootsViaRelayStorePallet;
 pub use verifier::*;