如何使用Bouncy Castle库在C#中使用PGP密钥签署txt文件

public void SignFile(String fileName,Stream privateKeyStream,String privateKeyPassword,Stream outStream)
{

    PgpSecretKey pgpSec = ReadSigningSecretKey(privateKeyStream);
    PgpPrivateKey pgpPrivKey = null;

    pgpPrivKey = pgpSec.ExtractPrivateKey(privateKeyPassword.ToCharArray());
    PgpSignatureGenerator sGen = new PgpSignatureGenerator(pgpSec.PublicKey.Algorithm,KeyStore.ParseHashAlgorithm(this.hash.ToString()));

    sGen.InitSign(PgpSignature.BinaryDocument,pgpPrivKey);

    foreach (string userId in pgpSec.PublicKey.GetUserIds()) {
        PgpSignatureSubpacketGenerator spGen = new PgpSignatureSubpacketGenerator();

        spGen.SetSignerUserId(false,userId);
        sGen.SetHashedSubpackets(spGen.Generate());
    }

    CompressionAlgorithmTag compression = PreferredCompression(pgpSec.PublicKey);
    PgpCompressedDataGenerator cGen = new PgpCompressedDataGenerator(compression);

    BcpgOutputStream bOut = new BcpgOutputStream(cGen.Open(outStream));
    sGen.GenerateOnePassVersion(false).Encode(bOut);

    FileInfo file = new FileInfo(fileName);
    FileStream fIn = new FileStream(fileName,FileMode.Open,FileAccess.Read,FileShare.Read);
    PgpLiteralDataGenerator lGen = new PgpLiteralDataGenerator();
    Stream lOut = lGen.Open(bOut,PgpLiteralData.Binary,file);

    int ch = 0;
    while ((ch = fIn.ReadByte()) >= 0) {
        lOut.WriteByte((byte)ch);
        sGen.Update((byte) ch);
    }

    fIn.Close();
    sGen.Generate().Encode(bOut);
    lGen.Close();
    cGen.Close();
    outStream.Close();
}

public PgpSecretKey ReadSigningSecretKey(Stream inStream)
// throws IOException,PGPException,WrongPrivateKeyException
{        
    PgpSecretKeyRingBundle pgpSec = CreatePgpSecretKeyRingBundle(inStream);
    PgpSecretKey key = null;
    IEnumerator rIt = pgpSec.GetKeyRings().GetEnumerator();
    while (key == null && rIt.MoveNext())
    {
        PgpSecretKeyRing kRing = (PgpSecretKeyRing)rIt.Current;
        IEnumerator kIt = kRing.GetSecretKeys().GetEnumerator();
        while (key == null && kIt.MoveNext()) 
        {
            PgpSecretKey k = (PgpSecretKey)kIt.Current;
            if(k.IsSigningKey)
                key = k;
        }
    }

    if(key == null)
      throw new WrongPrivateKeyException("Can't find signing key in key ring.");
    else
        return key;
}