如何使用BouncyCastle验证打开PGP签名

Question

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private bool VerifyWithPublicKey(string data, byte[] sig)
    {
        RSACryptoServiceProvider rsa;

        using (var keyreader = new StringReader(publicKey))
        {
                var pemReader = new PemReader(keyreader);
                var y = (RsaKeyParameters)pemReader.ReadObject();
                rsa = (RSACryptoServiceProvider)RSA.Create();
                var rsaParameters = new RSAParameters();

                rsaParameters.Modulus = y.Modulus.ToByteArray();
                rsaParameters.Exponent = y.Exponent.ToByteArray();
                rsa.ImportParameters(rsaParameters);

                // compute sha1 hash of the data
                var sha = new SHA1CryptoServiceProvider();
                byte[] hash = sha.ComputeHash(Encoding.ASCII.GetBytes(data));

                // This always returns false
                return rsa.VerifyHash(hash, CryptoConfig.MapNameToOID("SHA1"), sig);
        }

Answer 1

使用RSA不是您的情况。你需要

1. 定义公钥
2. 将公用ket转换为PGPPublicKey
3. 获取PgpSignature对象
4. 验证签名

要验证签名，您将需要已签名的原始数据。

public class iTransactVerifier
{
    private const string PublicKey = @"-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: 4.5

mQCNAjZu
-----END PGP PUBLIC KEY BLOCK-----";

    public static bool Verify(string signature, string data)
    {
        var inputStream = ConvertStringToStream(signature);

        PgpPublicKey publicKey = ReadPublicKeyFromString();
        var stream = PgpUtilities.GetDecoderStream(inputStream);

        PgpObjectFactory pgpFact = new PgpObjectFactory(stream);

        PgpSignatureList sList = pgpFact.NextPgpObject() as PgpSignatureList;
        if (sList == null)
        {
            throw new InvalidOperationException("PgpObjectFactory could not create signature list");
        }
        PgpSignature firstSig = sList[0];

        firstSig.InitVerify(publicKey);
        firstSig.Update(Encoding.UTF8.GetBytes(data));

        var verified = firstSig.Verify();
        return verified;
    }

    ....

    private static PgpPublicKey ReadPublicKeyFromString()
    {
        var varstream = ConvertStringToStream(PublicKey);
        var stream = PgpUtilities.GetDecoderStream(varstream);

        PgpObjectFactory pgpFact = new PgpObjectFactory(stream);
        var keyRing = (PgpPublicKeyRing)pgpFact.NextPgpObject();
        return keyRing.GetPublicKey();
    }
}