SafeSigner

The purpose of SafeSigner is to enable developers to sign messages and transactions from their preferred browser or mobile wallet without increasing your surface area for hacks by requiring you to view, copy and paste your private key.

TODO

• [x] Add message signing method
• [x] Add message (EIP712) signing method
• [x] Add Transaction signing method
• [x] From contract deployment processes
• [x] From any other process that needs a signature
• [x] Add Sign out button
• [x] Add message standard that handles message type, network, data, etc.
• [x] Add ability to change networks
• [x] Bubble up front end errors such as transaction rejections to back end
• [x] Clean up api responses
• [x] Safely handle when wallet doesn't have the requested chain
• [x] Detect chain from transaction and remove top level chain property
• [ ] Return connected address somewhere
• [x] Add Custom Chain Support
• [ ] Add Readme instructions for api use
• [ ] Add "Ready to sign" button so that users can change their wallet before being flooded with requests

How to use

SafeSigner supports signing arbitrary messages, typed messages (EIP712) and broadcasting transactions. Under the hood we are using the Viem methods SignMessage, SignTypedData and PrepareTransactionRequest. Our SafeSignerRequest type is just a wrapper over the parameter types for each of these methods.

You can import the SafeSigner class and use it like so:

// Start the service
const signer = new SafeSigner();
await signer.start();

const request: SafeSignerRequest = {
    message: 'Hello, world!'
};

// Send a message to be signed by the user
const { data: signedMessage, error } = await signer.signRequest(request);

Options Parameter

The signRequest method accepts an optional second parameter options:

• address: If specified, SafeSigner will enforce that the user connects with this exact wallet address before allowing them to sign.

const { data: signedMessage, error } = await signer.signRequest(request, {
    address: '0x1234567890123456789012345678901234567890'
});

API Use

You can also interact with SafeSigner through an API:

    npx tsx ./start.ts # This starts the server so that requests can be received
    
    # Basic request
    curl -X POST \
        -H 'Content-Type: application/json' \
        -d '{"request": {"message": "Hello, world!"}}' \
        http://localhost:3000/api/submit-request

    # Request with address enforcement
    curl -X POST \
        -H 'Content-Type: application/json' \
        -d '{"request": {"message": "Hello, world!"}, "options": {"address": "0x1234567890123456789012345678901234567890"}}' \
        http://localhost:3000/api/submit-request

Running the Example

The repository includes an example.ts file that demonstrates how to use SafeSigner. Here's how to run it:

Running with tsx

There are a few options for running the example:

Option 1: Using npx (Recommended)

npx tsx example.ts

Option 2: Install tsx globally

1. Install tsx globally (if not already installed):

   npm install -g tsx

2. Run the example:

   tsx example.ts

What happens

• The SafeSigner service starts and opens a web interface in your browser
• A few different types of signature requests are sent to the web interface
• You'll see multiple signing requests in your wallet
• After signing, the returned signatures or transaction hashes are logged to the console

Example Output

Ready on http://localhost:3000
SafeSigner started
Asking for signature on message
Client connected
 ○ Compiling / ...
 ✓ Compiled / in 1214ms (1969 modules)
 GET / 200 in 2237ms
Client connected
Client is ready
SafeSigner: Client is ready
Message signature: {
  data: '0x6a63a187cc2511029b4ef4a73c0d5fba53ed6fc57976c0d472b1b4634eade9ae681d59362382e484189e9660f972056c49633236deeaa546ebd611e66b77dea61c'
}
Asking for signature on EIP712 Typed Data Message
Typed message signature: {
  data: '0xdd04019990bb8f84b47f9e166277a65114724a9b96f72c6fa7c09cf180431e731ed9754134badd4d9c3cc60dc8b4523e9c6143e3871d6d0387e860b58afa95f11b'
}
....

Customizing the Example

You can modify example.ts to test different types of requests:

• Message signing: Change the request object to use message instead of transaction parameters
• Typed data signing: Use types and domain for EIP-712 signing
• Transaction signing and broadcasting: Provide transaction parameters (like to, value, chain, etc.) to sign and send a transaction; the returned value will be the transaction hash.
• Different networks: Modify the chain parameter to use other networks

Limitations

Because you have to sign each request manually from your wallet this method is not practical for signing dozens of transactions in one sitting unless you have great patience. 🧘