I am trying to sign a file with the private key and the hash algorithm read from a certificate and I cannot find a way to do it programmatically:

public byte[] SignFile(string filePath, X509Certificate2 certificate)
{
    using var rsaPrivateKey = certificate.GetRSAPrivateKey();
    using var fileStream = this.fileSystem.OpenFile(filePath, FileMode.Open, FileAccess.Read);
    var hashAlgorithmFromTheCertificate = HashAlgorithmName.SHA1; // <== How to get this from the certificate instead of hard-coding it?
    return rsaPrivateKey!.SignData(fileStream, hashAlgorithmFromTheCertificate, RSASignaturePadding.Pss);
} 

I have seen the Reflection-based solution here:
How to retrieve the Signature hash algorithm friendly name using c# cryptography?

Is there a clean way to do it or are we stuck with Reflection?

I am using:

BouncyCastle.Cryptography Version=”2.4.0″

Thanks in advance

I have tried to use:

var algoName = HashAlgorithmName.FromOid(certificate.SignatureAlgorithm.Value!);

But it throws:

The specified OID (XXXXXXXXXXXX) does not represent a known hash algorithm