Crate ethers_signer_factory 

Key Derivation and Signing Functions

This crate provides a set of functions for key derivation and signing of Ethereum transactions and messages. It uses the HKDF (HMAC-based Key Derivation Function) with SHA-512 as the base key derivation algorithm and SHA-256 for expanding keys.

Functions

• get_derived_key: Computes a derived key of length SHA256_OUTPUT_LEN bytes using HKDF-SHA512.
• get_wallet_address: Computes the Ethereum address associated with a derived key.
• sign_transaction: Signs an Ethereum transaction using a derived key and returns the generated signature.
• sign_message: Signs an Ethereum message using a derived key and returns the generated signature.
• sign_typed_data: Sign EIP-712 typed data using a derived key and returns the generated signature.
• get_signer: Returns a signer wallet from a derived key with an chain ID.

Example

#[tokio::main]
async fn main() {
    use ethers_signer_factory::{get_derived_key, get_wallet_address, sign_transaction, sign_message, sign_typed_data, get_signer};
    use ethers_contract_derive::{Eip712, EthAbiType};
    use ethers_core::types::transaction::eip2718::TypedTransaction;
    use ethers_core::types::{TransactionRequest, Address};
    
    let key: [u8; 64] = [0u8; 64];
    let salt: [u8; 64] = [0u8; 64];
    let info = "some_key_id";
    
    // Example 1: Derive a key.
    let derived_key = get_derived_key(&key, &salt, info).expect("Key derivation failed");
    assert_eq!(
        hex::encode(derived_key).as_str(),
        "de61002dc1676e6b59b2dd27da3f32280defe3bc384f77de6eee372f70ceaae7"
    );
    
    // Example 2: Get an Ethereum address from the derived key.
    let wallet_address: Address = get_wallet_address(&key, &salt, info).expect("Wallet creation failed");
    assert_eq!(
        hex::encode(wallet_address.as_bytes()).as_str(),
        "ea4d3e00f3d283cdb0e4d4fb783f208a5095fcb7"
    );
    
    // Example 3. Get a Signer Wallet from the derived key.
    let chain_id = 1;
    let _wallet = get_signer(&key, &salt, info, chain_id).expect("Signer creation failed");
    
    // Example 4: Sign a transaction.
    let tx = TypedTransaction::Legacy(TransactionRequest::default().from(wallet_address));
    let signed_tx =
        sign_transaction(&key, &salt, info, &tx).expect("Transaction signing failed");
    
    assert_eq!(
        hex::encode(signed_tx.to_vec().as_slice()).as_str(),
        "815dd9b736c52fed571b2d5d985c52d78593a6d4a602f8455e884371270760132c8cd1f163af8303dc83aaaf48d2a03bff3697f6c922951809c19c0593841b3426"
    );
    
    // Example 5: Sign a message.
    let message = "Some message to sign";
    let signature = sign_message(&key, &salt, info, message).expect("Message signing failed");
    
    assert_eq!(
        hex::encode(signature.to_vec().as_slice()).as_str(),
        "35867e62e5a2c4dd52947c0cbb4af6afc95564d5abb0584bec2f9669046f81aa0d22dba8e6844fb125b93fec9a3e3684916dc4541e45bdc824cf18b5ab2409c81c"
    );
    
    // Example 6: Sign Typed data.
    #[derive(Clone, Default, EthAbiType, Eip712)]
    struct TestTypedData {
        value: u32,
    }
    
    let test_payload = TestTypedData { value: 1 };
    let signature = sign_typed_data(&key, &salt, info, &test_payload)
        .await
        .expect("Sign typed data failed");
    
    assert_eq!(
        hex::encode(signature.to_vec().as_slice()).as_str(),
        "cdd86e133a50b7d2c4f5bff092dbfe4086ed559bb0718e9c1c9bce31171f0ff44df3cc0dcd20388ad99be26b6eca0c104bff48eb6ad8135bec9d76aee2c6930f1b"
    );
}

Dependencies

This crate depends on the following external libraries:

• ethers_core: Ethereum core library for types and utilities.
• ethers_signers: Ethereum wallet and signing functionality.
• ring: Cryptographic library for key derivation.
• hex: Hex strings encoding and decoding library.

Error Handling

Functions in this crate return a Result type that can contain errors specific to key derivation and signing. Refer to the individual function documentation for details on error types and how to handle them.

Modules

error

Functions

get_derived_key

Derives a cryptographic key of length 32 bytes using the HKDF-SHA512 key derivation function. The input key and salt must both be 64 bytes each.

get_signer

Gets a signer wallet from a derived key with an optional chain ID.

get_wallet_address

Derives a wallet address from the given input key material, salt, and info string.

sign_message

Signs a message using a derived key, salt, and info string.

sign_transaction

Signs a TypedTransaction using a derived key, salt, and info string.

sign_typed_data

Signs typed data using a derived key and returns the generated signature.