Translate RSA verification algorithm from NodeJS to .Net Core for biometric data

Question

I'm trying to replicate a third-party NodeJS algorithm in .Net Core to verify a RSA payload and signature. The algorithm is used by a mobile app to verify biometric data. This is the thir-party NodeJS code:

import NodeRSA from "node-rsa";

export const verifySignature = (
  base64Signature: string,
  payload: string,
  publicKey: string
): boolean => {
  const key = new NodeRSA();
  const publicKeyBuffer = Buffer.from(publicKey, "base64");
  const signer = key.importKey(publicKeyBuffer, "pkcs8-public-der");

  return key.verify(Buffer.from(payload), base64Signature, "utf8", "base64");
};

The publicKey is a base64 string coming from a database, base64signature and payload come from the body on an API call. I asked to the third-party developer some base64signature and payload which works on his code, but I can't make them work with my .Net function:

using System.Security.Cryptography;

private bool VerifySignature(string base64Signature, string payload, string publicKey)
{
    RSA rsa = new RSACryptoServiceProvider();
    rsa.ImportSubjectPublicKeyInfo(Convert.FromBase64String(publicKey), out _);
    return rsa.VerifyData(Encoding.UTF8.GetBytes(payload), Convert.FromBase64String(base64Signature), HashAlgorithmName.MD5, RSASignaturePadding.Pkcs1);
}

I have no idea where is the error, maybe the HashAlgorithmName.MD5 or the RSASignaturePadding.Pkcs1 parameters? I have no access to the mobile app code, so I don't know which paramters to use.

Any suggestion?

Thank you, Sebasthian

Answer 1

From the documentation of Node-RSA:

signingScheme — scheme used for signing and verifying. Can be 'pkcs1' or 'pss' or 'scheme-hash' format string (eg 'pss-sha1'). Default 'pkcs1-sha256', or, if chosen pss: 'pss-sha1'.