Merge pull request #1487 from opentensor/associate-evm-key

Create extrinsic to allow EVM key association

Author: sam0x17

Diff for: Cargo.lock

@@ -67,6 +67,7 @@ futures = "0.3.30"
 hex = { version = "0.4", default-features = false }
 hex-literal = "0.4.1"
 jsonrpsee = { version = "0.24.4", default-features = false }
+libsecp256k1 = { version = "0.7.2", default-features = false }
 log = { version = "0.4.21", default-features = false }
 memmap2 = "0.9.4"
 ndarray = { version = "0.15.6", default-features = false }

Diff for: Cargo.toml

@@ -34,6 +34,7 @@ serde_bytes = { workspace = true, features = ["alloc"] }
 serde_with = { workspace = true, features = ["macros"] }
 sp-runtime = { workspace = true }
 sp-std = { workspace = true }
+libsecp256k1 = { workspace = true }
 log = { workspace = true }
 substrate-fixed = { workspace = true }
 pallet-transaction-payment = { workspace = true }
@@ -91,6 +92,7 @@ std = [
 	"sp-tracing/std",
 	"sp-version/std",
 	"hex/std",
+	"libsecp256k1/std",
 	"log/std",
 	"ndarray/std",
 	"serde/std",

Diff for: pallets/subtensor/Cargo.toml

@@ -77,7 +77,7 @@ pub mod pallet {
     };
     use frame_system::pallet_prelude::*;
     use pallet_drand::types::RoundNumber;
-    use sp_core::{ConstU32, H256};
+    use sp_core::{ConstU32, H160, H256};
     use sp_runtime::traits::{Dispatchable, TrailingZeroInput};
     use sp_std::collections::vec_deque::VecDeque;
     use sp_std::vec;
@@ -1561,6 +1561,14 @@ pub mod pallet {
         OptionQuery,
     >;
 
+    /// =============================
+    /// ==== EVM related storage ====
+    /// =============================
+    #[pallet::storage]
+    /// --- DMAP (netuid, uid) --> (H160, last_block_where_ownership_was_proven)
+    pub type AssociatedEvmAddress<T: Config> =
+        StorageDoubleMap<_, Twox64Concat, u16, Twox64Concat, u16, (H160, u64), OptionQuery>;
+
     /// ==================
     /// ==== Genesis =====
     /// ==================

Diff for: pallets/subtensor/src/lib.rs

@@ -9,6 +9,7 @@ mod dispatches {
     use frame_support::traits::schedule::DispatchTime;
     use frame_support::traits::schedule::v3::Anon as ScheduleAnon;
     use frame_system::pallet_prelude::BlockNumberFor;
+    use sp_core::ecdsa::Signature;
     use sp_runtime::traits::Saturating;
 
     use crate::MAX_CRV3_COMMIT_SIZE_BYTES;
@@ -1929,6 +1930,50 @@ mod dispatches {
             Ok(())
         }
 
+        /// Attempts to associate a hotkey with an EVM key.
+        ///
+        /// The signature will be checked to see if the recovered public key matches the `evm_key` provided.
+        ///
+        /// The EVM key is expected to sign the message according to this formula to produce the signature:
+        /// ```text
+        /// keccak_256(hotkey ++ keccak_256(block_number))
+        /// ```
+        ///
+        /// # Arguments
+        /// * `origin` - The origin of the transaction, which must be signed by the coldkey that owns the `hotkey`.
+        /// * `netuid` - The netuid that the `hotkey` belongs to.
+        /// * `hotkey` - The hotkey associated with the `origin`.
+        /// * `evm_key` - The EVM key to associate with the `hotkey`.
+        /// * `block_number` - The block number used in the `signature`.
+        /// * `signature` - A signed message by the `evm_key` containing the `hotkey` and the hashed `block_number`.
+        ///
+        /// # Errors
+        /// Returns an error if:
+        /// * The transaction is not signed.
+        /// * The hotkey is not owned by the origin coldkey.
+        /// * The hotkey does not belong to the subnet identified by the netuid.
+        /// * The EVM key cannot be recovered from the signature.
+        /// * The EVM key recovered from the signature does not match the given EVM key.
+        ///
+        /// # Events
+        /// May emit a `EvmKeyAssociated` event on success
+        #[pallet::call_index(93)]
+        #[pallet::weight((
+            Weight::from_parts(3_000_000, 0).saturating_add(T::DbWeight::get().reads_writes(2, 1)),
+            DispatchClass::Operational,
+            Pays::Yes
+        ))]
+        pub fn associate_evm_key(
+            origin: T::RuntimeOrigin,
+            netuid: u16,
+            hotkey: T::AccountId,
+            evm_key: H160,
+            block_number: u64,
+            signature: Signature,
+        ) -> DispatchResult {
+            Self::do_associate_evm_key(origin, netuid, hotkey, evm_key, block_number, signature)
+        }
+
         /// Recycles alpha from a cold/hot key pair, reducing AlphaOut on a subnet
         ///
         /// # Arguments

Diff for: pallets/subtensor/src/macros/dispatches.rs

@@ -203,5 +203,9 @@ mod errors {
         NotEnoughAlphaOutToRecycle,
         /// Cannot burn or recycle TAO from root subnet
         CannotBurnOrRecycleOnRootSubnet,
+        /// Public key cannot be recovered.
+        UnableToRecoverPublicKey,
+        /// Recovered public key is invalid.
+        InvalidRecoveredPublicKey,
     }
 }

Diff for: pallets/subtensor/src/macros/errors.rs

@@ -294,6 +294,18 @@ mod events {
         /// (coldkey, hotkey, amount, subnet_id)
         AlphaBurned(T::AccountId, T::AccountId, u64, u16),
 
+        /// An EVM key has been associated with a hotkey.
+        EvmKeyAssociated {
+            /// The subnet that the hotkey belongs to.
+            netuid: u16,
+            /// The hotkey associated with the EVM key.
+            hotkey: T::AccountId,
+            /// The EVM key being associated with the hotkey.
+            evm_key: H160,
+            /// The block where the association happened.
+            block_associated: u64,
+        },
+
         /// CRV3 Weights have been successfully revealed.
         ///
         /// - **netuid**: The network identifier.