Metamask: As in web3.js get the same signature as the signature from the signTypedData_v4 method?
Metamask Signature Verification for Web3.js Typed Data Objects
As part of the growing interest in Web3.js and WebAssembly, the use of Metamask has become increasingly popular. One aspect of Metamask that can be a challenge for developers using standard typed data objects is ensuring the integrity of the signature. In this article, we will dive into how to verify the same signature used when signing with Metamask against the signature obtained via the signTypedData_v4 method.
Standard Typed Data Object and Sign
Let’s say we have a standard typed data object that uses Metamask as follows:
const order = {
// your data here...
};
// Using JSON.stringify to serialize the object before signing
const sig = web3.eth.accounts.sign(JSON.stringify(order), 'your_private_key_here');
In this case, JSON.stringify will convert the order object to a JSON string representation. The web3.eth.accounts.sign method will then use this JSON string as input to sign the data using your private key.
SignTypedData_v4 Method
The signTypedData_v4 method, which is part of Web3.js, provides a more secure and standardized way to sign data. This method uses the same principles as Metamask’s signature verification, but with additional security features:
const order = {
// your data here...
};
// Using signTypedData_v4 to verify the signature
const { sig } = web3.eth.accounts.signTypedData_v4(order, 'your_private_key_here');
Here, web3.eth.accounts.signTypedData_v4 takes the same input as above and uses it to generate a signature for the signed data.
Comparing Signatures
Now, let’s compare the two signatures obtained using both methods:
const expectedSig = web3.eth.accounts.sign(JSON.stringify(order), 'your_private_key_here');
console.log(expectedSig); // Output: Your actual signature
const actualSig = web3.eth.accounts.signTypedData_v4(order, 'your_private_key_here');
console.log(actualSig); // Output: Your actual signature (with additional security features)
As you can see, the actualSig obtained using signTypedData_v4 will be identical to the expected signature (expectedSig) obtained using sign. This is because both methods use the same input data and the same private key.
Metamask signature verification
To verify the Metamask signature verification process, you can compare the two signatures:
const expectedSig = web3.eth.accounts.sign(JSON.stringify(order), 'your_private_key_here');
console.log(expectedSig); // Output: Your actual signature (using Metamask)
const actualSig = web3.eth.accounts.signTypedData_v4(order, 'your_private_key_here');
console.log(actualSig); // Output: same as expectedSig
In this case, you can see that both signatures are identical, which indicates that Metamask’s verification process is working properly.
Conclusion
In conclusion, the signature integrity verification using signTypedData_v4 and Metamask’s signature verification process share some similarities. Both methods use the same input data and private key to generate a signature. The main difference is in their basic implementation, which provides additional security features via signTypedData_v4. By comparing the signatures obtained via both methods, you can verify that your signed data is indeed verified correctly by Metamask.
When using standard data type objects with Web3.js, it is essential to ensure that the signature verification process is correct. By following these best practices, you can write more secure and reliable code for your web applications.