EVM Sign-in

EVM Sign-in means users can use their EVM wallets to interact with sidechain using direct invocations. This is achieved both by mapping EVM address to Substrate address space and by supporting EVM signature scheme.

Signature verification

Now sidechain worker supports two new types of signatures:

• Ethereum

• EthereumPrettified

They both use ECDSA secp256k1 to verify signature correctness. The difference is that the latter uses "Litentry authorization token:" prefix to assure user that the transaction payload is generated within Litentry context.

Address mapping

All IdGraphs are stored inside substrate's pallet storage and identified by user's AccountId. This requires an address mapping from EVM format to Substrate format for all interactions originating from EVM wallets. We use a one-way mapping procedure.

Mapping procedure:

1. Take 20 bytes of EVM address

2. Prepend them with evm:

3. Compute Blake2-256

4. Create 32 bytes AccountId from hash result