add eip191 prefix to eth_sign and personal_sign (#474)

* add prefix to eth_sign and personal_sign

* format import

Author: mokita-j

crates/anvil-polkadot/src/api_server/signer.rs

@@ -3,7 +3,7 @@ use crate::api_server::{
     revive_conversions::ReviveAddress,
 };
 use alloy_dyn_abi::TypedData;
-use alloy_primitives::Address;
+use alloy_primitives::{Address, utils::eip191_hash_message};
 use polkadot_sdk::pallet_revive::evm::{Account, TransactionSigned, TransactionUnsigned};
 use std::collections::HashMap;
 use subxt::utils::H160;
@@ -46,7 +46,8 @@ impl DevSigner {
             .keypairs
             .get(&ReviveAddress::from(address).inner())
             .ok_or(Error::NoSignerAvailable)?;
-        let mut signature = keypair.sign(message).0;
+        let hash = eip191_hash_message(message);
+        let mut signature = keypair.sign_prehashed(hash.as_ref()).0;
         signature[64] = Self::recovery_id_mapper(signature[64]);
         Ok(signature)
     }