充气城堡 C# PGP 解密示例

终于让它工作了。我对其他示例的主要问题是，我的私钥环包含一个用于签名的密钥，该密钥在尝试加载密钥进行解密时首先出现。这就是为什么我必须在密钥上添加对ElGamalPrivateKeyParameters类型的检查。

下面是我的代码。不是很干净，但它有效。

        private static PgpPrivateKey GetPrivateKey(string privateKeyPath)
    {
        using (Stream keyIn = File.OpenRead(privateKeyPath))
        using (Stream inputStream = PgpUtilities.GetDecoderStream(keyIn))
        {
            PgpSecretKeyRingBundle secretKeyRingBundle = new PgpSecretKeyRingBundle(inputStream);
            PgpSecretKey key = null;
            foreach (PgpSecretKeyRing kRing in secretKeyRingBundle.GetKeyRings())
            {
                foreach (PgpSecretKey secretKey in kRing.GetSecretKeys())
                {
                    PgpPrivateKey privKey = secretKey.ExtractPrivateKey("1234567890".ToCharArray());
                    if (privKey.Key.GetType() ==
                        typeof (Org.BouncyCastle.Crypto.Parameters.ElGamalPrivateKeyParameters))
                        //Org.BouncyCastle.Crypto.Parameters.ElGamalPrivateKeyParameters
                    {
                        return privKey;
                    }
                }
            }
        }
        
        return null;
    }


    public static void Decrypt(Stream input, string outputpath, String privateKeyPath)
    {
        input = PgpUtilities.GetDecoderStream(input);
        try
        {
            PgpObjectFactory pgpObjF = new PgpObjectFactory(input);
            PgpEncryptedDataList enc;
            PgpObject obj = pgpObjF.NextPgpObject();
            if (obj is PgpEncryptedDataList)
            {
                enc = (PgpEncryptedDataList)obj;
            }
            else
            {
                enc = (PgpEncryptedDataList)pgpObjF.NextPgpObject();
            }
       

            
            PgpPrivateKey privKey = GetPrivateKey(privateKeyPath);

            PgpPublicKeyEncryptedData pbe = enc.GetEncryptedDataObjects().Cast<PgpPublicKeyEncryptedData>().First();
            Stream clear;
            clear = pbe.GetDataStream(privKey);
            PgpObjectFactory plainFact = new PgpObjectFactory(clear);
            PgpObject message = plainFact.NextPgpObject();
            if (message is PgpCompressedData)
            {
                PgpCompressedData cData = (PgpCompressedData)message;
                Stream compDataIn = cData.GetDataStream();
                PgpObjectFactory o = new PgpObjectFactory(compDataIn);
                message = o.NextPgpObject();
                if (message is PgpOnePassSignatureList)
                {
                    message = o.NextPgpObject();
                    PgpLiteralData Ld = null;
                    Ld = (PgpLiteralData)message;
                    Stream output = File.Create(outputpath + "''" + Ld.FileName);
                    Stream unc = Ld.GetInputStream();
                    Streams.PipeAll(unc, output);
                }
                else
                {
                    PgpLiteralData Ld = null;
                    Ld = (PgpLiteralData)message;
                    //Stream output = File.Create(outputpath + "''" + Ld.FileName);
                    Stream output = File.Create(outputpath);
                    Stream unc = Ld.GetInputStream();
                    Streams.PipeAll(unc, output);
                }
            }
        }
        catch (Exception e)
        {
            throw new Exception(e.Message);
        }
    }

我在 Ron Harlev 的 Decrypt 函数保存输出文件时遇到了问题，直到程序终止。我围绕 Stream 添加了一些使用语句来克服这个问题。我还替换了硬编码的密码短语，以支持输入参数。我希望有人觉得这有用。

private static bool DecryptFile(Stream inputStream, string outputDir, char[] passPhrase, string privateKeyLoc)
    {
        try
        {
            using (var newStream = PgpUtilities.GetDecoderStream(inputStream))
            {
                PgpObjectFactory pgpObjF = new PgpObjectFactory(newStream);
                PgpEncryptedDataList enc;
                PgpObject obj = pgpObjF.NextPgpObject();
                if (obj is PgpEncryptedDataList)
                {
                    enc = (PgpEncryptedDataList)obj;
                }
                else
                {
                    enc = (PgpEncryptedDataList)pgpObjF.NextPgpObject();
                }
                PgpPrivateKey privKey = GetPrivateKey(privateKeyLoc, passPhrase, logger);
                PgpPublicKeyEncryptedData pbe = enc.GetEncryptedDataObjects().Cast<PgpPublicKeyEncryptedData>().First();
                using (Stream clear = pbe.GetDataStream(privKey))
                {
                    PgpObjectFactory plainFact = new PgpObjectFactory(clear);
                    PgpObject message = plainFact.NextPgpObject();
                    if (message is PgpCompressedData)
                    {
                        PgpCompressedData cData = (PgpCompressedData)message;
                        Stream compDataIn = cData.GetDataStream();
                        PgpObjectFactory o = new PgpObjectFactory(compDataIn);
                        message = o.NextPgpObject();
                        if (message is PgpOnePassSignatureList)
                        {
                            message = o.NextPgpObject();
                        }
                        PgpLiteralData Ld = null;
                        Ld = (PgpLiteralData)message;
                        using (Stream output = File.Create(outputDir + "''" + Ld.FileName))
                        {
                            Stream unc = Ld.GetInputStream();
                            Streams.PipeAll(unc, output);
                        }
                    }
                }
            }
            return true;
        }
        catch (Exception e)
        {
            throw new Exception(e.Message);
            return false;
        }
    }