我们使用 BouncyCastle API 为客户端加密文件。他得到了“仅限您的眼睛”的字样。尝试解密时来自 PGP 的消息。为什么？

Question

我们使用 Bouncy.Castle C# API 进行 PGP 加密。我绝不是 PGP 加密和各种可用选项方面的专家。

加密似乎运行良好，但是，当客户端尝试解密时，他说 PGP 不会输出到文件，而只会输出到屏幕，因为它被标记为“仅供您查看”。这是 --verbose 消息：

pgp --decrypt Client_FileExport_20110510_020011.zip.pgp
  Client_FileExport_20110511_132203.zip.pgp --info verbose

McAfee E-Business Server v8.5 - Full License
(c) 1991-2006 McAfee, Inc.  All Rights Reserved.

Setting temporary directory to C:\DOCUME~1\$963\LOCALS~1\Temp\
Decoding data....

event 1: initial
event 13: BeginLex
event 8: Analyze
File is encrypted.  event 9: Recipients
Secret key is required to read it.
Key for user ID "Client_RSAv4_Key <[email protected]>"
event 6: Passphrase
You need a pass phrase to unlock your secret key.

Enter pass phrase:

event 23: Decryption

symmetric cipher used: CAST5
event 11: Output options
typecode: 0062
for your eyes only


This message is marked "For your eyes only".  Display now (Y/n)?

我不知道如何调试它。有人知道吗？

这是我们用来加密数据的通用代码。在这种情况下，我们不会签署文档，因此可以忽略该部分代码。

private void EncryptImpl(Stream inputStream, Stream outputStream, bool signOutput)
    {
        const int BUFFER_SIZE = 1 << 16; // should always be power of 2
        bool armor = true;
        bool withIntegrityCheck = true;

        if (armor)
            outputStream = new ArmoredOutputStream(outputStream);

        var encKey = PgpHelper.ReadPublicKey(this.EncryptionPublicKey);

        // Init encrypted data generator
        PgpEncryptedDataGenerator encryptedDataGenerator =
            new PgpEncryptedDataGenerator(SymmetricKeyAlgorithmTag.Cast5, withIntegrityCheck, new SecureRandom());
        encryptedDataGenerator.AddMethod(encKey);
        Stream encryptedOut = encryptedDataGenerator.Open(outputStream, new byte[BUFFER_SIZE]);

        // Init compression
        PgpCompressedDataGenerator compressedDataGenerator = new PgpCompressedDataGenerator(CompressionAlgorithmTag.Zip);
        Stream compressedOut = compressedDataGenerator.Open(encryptedOut);

        PgpSignatureGenerator signatureGenerator = null;
        if (signOutput)
        {
            // Init signature
            var pgpSecKey = PgpHelper.ReadSecretKey(this.OrigamiSecretKey);
            PgpPrivateKey pgpPrivKey = pgpSecKey.ExtractPrivateKey(this.PassPhrase.ToCharArray());
            signatureGenerator = new PgpSignatureGenerator(pgpSecKey.PublicKey.Algorithm, HashAlgorithmTag.Sha1);
            signatureGenerator.InitSign(PgpSignature.BinaryDocument, pgpPrivKey);
            foreach (string userId in pgpSecKey.PublicKey.GetUserIds())
            {
                PgpSignatureSubpacketGenerator spGen = new PgpSignatureSubpacketGenerator();
                spGen.SetSignerUserId(false, userId);
                signatureGenerator.SetHashedSubpackets(spGen.Generate());
                // Just the first one!
                break;
            }
            signatureGenerator.GenerateOnePassVersion(false).Encode(compressedOut);
        }

        // Create the Literal Data generator output stream
        PgpLiteralDataGenerator literalDataGenerator = new PgpLiteralDataGenerator();

        // TODO: Use lastwritetime from source file
        Stream literalOut = literalDataGenerator.Open(compressedOut, PgpLiteralData.Binary,
            PgpLiteralDataGenerator.Console, DateTime.Now, new byte[BUFFER_SIZE]);

        // Open the input file
        byte[] buf = new byte[BUFFER_SIZE];
        int len;
        while ((len = inputStream.Read(buf, 0, buf.Length)) > 0)
        {
            literalOut.Write(buf, 0, len);

            if (signOutput)
                signatureGenerator.Update(buf, 0, len);
        }

        literalOut.Close();
        literalDataGenerator.Close();

        if (signOutput)
            signatureGenerator.Generate().Encode(compressedOut);

        compressedOut.Close();
        compressedDataGenerator.Close();
        encryptedOut.Close();
        encryptedDataGenerator.Close();
        inputStream.Close();

        if (armor)
            outputStream.Close();
    }

Answer 1

我猜测是 PgpLiteralDataGenerator.Console 导致它仅显示在客户端计算机的控制台中。

Stream literalOut = literalDataGenerator.Open(
    compressedOut, 
    PgpLiteralData.Binary,             
    PgpLiteralDataGenerator.Console,
    DateTime.Now, 
    new byte[BUFFER_SIZE]);

Answer 2

当加密文件不包含原始文件的名称时，会显示此消息。如果您不加密文件，则可以将几乎任何内容放入该字段（假定它构成文件名，对目标系统有效）。