Question

让我首先说我对这一切都是新手。我想要做的是在Java中使用gpg来解密加密文件。

我成功完成了什么：

如果同事使用我的公钥和他的私钥加密文件并成功解密它。
走另一条路
让另一位同事试图解密一个不适合他的文件：失败（如预期的那样）

我的密钥是这样生成的......

（gpg --version告诉我我正在使用1.4.5而我正在使用Bouncy Castle 1.47）

gpg --gen-ley

选择选项“DSA和Elgamal（默认）”

填写其他字段并生成密钥。

使用我的公钥和另一个密钥加密文件。我想解密它。我编写了以下Java代码来完成此任务。我正在使用几种不推荐使用的方法，但我无法弄清楚如何正确实现使用非弃用版本所需的工厂方法，所以如果有人对我应该使用的那些实现有一个想法，那将是一个不错的奖金。

    Security.addProvider(new BouncyCastleProvider());

        PGPSecretKeyRingCollection secretKeyRing = new PGPSecretKeyRingCollection(new FileInputStream(new File("test-files/secring.gpg")));
        PGPSecretKeyRing pgpSecretKeyRing = (PGPSecretKeyRing) secretKeyRing.getKeyRings().next();
        PGPSecretKey secretKey = pgpSecretKeyRing.getSecretKey();
        PGPPrivateKey privateKey = secretKey.extractPrivateKey("mypassword".toCharArray(), "BC");

        System.out.println(privateKey.getKey().getAlgorithm());
        System.out.println(privateKey.getKey().getFormat());

        PGPObjectFactory pgpF = new PGPObjectFactory(
    new FileInputStream(new File("test-files/test-file.txt.gpg")));
        Object pgpObj = pgpF.nextObject();
        PGPEncryptedDataList encryptedDataList = (PGPEncryptedDataList) pgpObj;

        Iterator objectsIterator = encryptedDataList.getEncryptedDataObjects();

        PGPPublicKeyEncryptedData publicKeyEncryptedData = (PGPPublicKeyEncryptedData) objectsIterator.next();
        InputStream inputStream = publicKeyEncryptedData.getDataStream(privateKey, "BC");

因此，当我运行此代码时，我了解到我的密钥的算法和格式如下：

算法：DSA 格式：PKCS＃8

然后它在最后一行打破了：

Exception in thread "main" org.bouncycastle.openpgp.PGPException: error setting asymmetric cipher
at org.bouncycastle.openpgp.operator.jcajce.JcePublicKeyDataDecryptorFactoryBuilder.decryptSessionData(Unknown Source)
at org.bouncycastle.openpgp.operator.jcajce.JcePublicKeyDataDecryptorFactoryBuilder.access$000(Unknown Source)
at org.bouncycastle.openpgp.operator.jcajce.JcePublicKeyDataDecryptorFactoryBuilder$2.recoverSessionData(Unknown Source)
at org.bouncycastle.openpgp.PGPPublicKeyEncryptedData.getDataStream(Unknown Source)
at org.bouncycastle.openpgp.PGPPublicKeyEncryptedData.getDataStream(Unknown Source)
at org.bouncycastle.openpgp.PGPPublicKeyEncryptedData.getDataStream(Unknown Source)
at org.bouncycastle.openpgp.PGPPublicKeyEncryptedData.getDataStream(Unknown Source)
at TestBouncyCastle.main(TestBouncyCastle.java:74)

引起：java.security.InvalidKeyException：传递给ElGamal的未知密钥类型在org.bouncycastle.jcajce.provider.asymmetric.elgamal.CipherSpi.engineInit（未知来源）在org.bouncycastle.jcajce.provider.asymmetric.elgamal.CipherSpi.engineInit（未知来源）在javax.crypto.Cipher.init（DashoA13 * ..）在javax.crypto.Cipher.init（DashoA13 * ..） ......还有8个

我在这里提出了许多建议，从“不要使用gpg，使用x代替”到“不要使用充气城堡，使用x代替”来介于两者之间。谢谢！

Answer 1

如果有兴趣知道如何使用bouncy castle openPGP库加密和解密gpg文件，请查看以下java代码：

以下是您需要的4种方法：

以下方法将从.asc文件中读取并导入您的密钥：

public static PGPSecretKey readSecretKeyFromCol(InputStream in, long keyId) throws IOException, PGPException {
    in = PGPUtil.getDecoderStream(in);
    PGPSecretKeyRingCollection pgpSec = new PGPSecretKeyRingCollection(in, new BcKeyFingerprintCalculator());

    PGPSecretKey key = pgpSec.getSecretKey(keyId);

    if (key == null) {
        throw new IllegalArgumentException("Can't find encryption key in key ring.");
    }
    return key;
}

以下方法将从.asc文件中读取并导入您的公钥：

@SuppressWarnings("rawtypes")
    public static PGPPublicKey readPublicKeyFromCol(InputStream in) throws IOException, PGPException {
        in = PGPUtil.getDecoderStream(in);
        PGPPublicKeyRingCollection pgpPub = new PGPPublicKeyRingCollection(in, new BcKeyFingerprintCalculator());
        PGPPublicKey key = null;
        Iterator rIt = pgpPub.getKeyRings();
        while (key == null && rIt.hasNext()) {
            PGPPublicKeyRing kRing = (PGPPublicKeyRing) rIt.next();
            Iterator kIt = kRing.getPublicKeys();
            while (key == null && kIt.hasNext()) {
                PGPPublicKey k = (PGPPublicKey) kIt.next();
                if (k.isEncryptionKey()) {
                    key = k;
                }
            }
        }
        if (key == null) {
            throw new IllegalArgumentException("Can't find encryption key in key ring.");
        }
        return key;
    }

以下2种解密和加密gpg文件的方法：

public void decryptFile(InputStream in, InputStream secKeyIn, InputStream pubKeyIn, char[] pass) throws IOException, PGPException, InvalidCipherTextException {
        Security.addProvider(new BouncyCastleProvider());

        PGPPublicKey pubKey = readPublicKeyFromCol(pubKeyIn);

        PGPSecretKey secKey = readSecretKeyFromCol(secKeyIn, pubKey.getKeyID());

        in = PGPUtil.getDecoderStream(in);

        JcaPGPObjectFactory pgpFact;


        PGPObjectFactory pgpF = new PGPObjectFactory(in, new BcKeyFingerprintCalculator());

        Object o = pgpF.nextObject();
        PGPEncryptedDataList encList;

        if (o instanceof PGPEncryptedDataList) {

            encList = (PGPEncryptedDataList) o;

        } else {

            encList = (PGPEncryptedDataList) pgpF.nextObject();

        }

        Iterator<PGPPublicKeyEncryptedData> itt = encList.getEncryptedDataObjects();
        PGPPrivateKey sKey = null;
        PGPPublicKeyEncryptedData encP = null;
        while (sKey == null && itt.hasNext()) {
            encP = itt.next();
            secKey = readSecretKeyFromCol(new FileInputStream("PrivateKey.asc"), encP.getKeyID());
            sKey = secKey.extractPrivateKey(new BcPBESecretKeyDecryptorBuilder(new BcPGPDigestCalculatorProvider()).build(pass));
        }
        if (sKey == null) {
            throw new IllegalArgumentException("Secret key for message not found.");
        }

        InputStream clear = encP.getDataStream(new BcPublicKeyDataDecryptorFactory(sKey));

        pgpFact = new JcaPGPObjectFactory(clear);

        PGPCompressedData c1 = (PGPCompressedData) pgpFact.nextObject();

        pgpFact = new JcaPGPObjectFactory(c1.getDataStream());

        PGPLiteralData ld = (PGPLiteralData) pgpFact.nextObject();
        ByteArrayOutputStream bOut = new ByteArrayOutputStream();

        InputStream inLd = ld.getDataStream();

        int ch;
        while ((ch = inLd.read()) >= 0) {
            bOut.write(ch);
        }

        //System.out.println(bOut.toString());

        bOut.writeTo(new FileOutputStream(ld.getFileName()));
        //return bOut;

    }

    public static void encryptFile(OutputStream out, String fileName, PGPPublicKey encKey) throws IOException, NoSuchProviderException, PGPException {
        Security.addProvider(new BouncyCastleProvider());

        ByteArrayOutputStream bOut = new ByteArrayOutputStream();

        PGPCompressedDataGenerator comData = new PGPCompressedDataGenerator(PGPCompressedData.ZIP);

        PGPUtil.writeFileToLiteralData(comData.open(bOut), PGPLiteralData.BINARY, new File(fileName));

        comData.close();

        PGPEncryptedDataGenerator cPk = new PGPEncryptedDataGenerator(new BcPGPDataEncryptorBuilder(SymmetricKeyAlgorithmTags.TRIPLE_DES).setSecureRandom(new SecureRandom()));

        cPk.addMethod(new BcPublicKeyKeyEncryptionMethodGenerator(encKey));

        byte[] bytes = bOut.toByteArray();

        OutputStream cOut = cPk.open(out, bytes.length);

        cOut.write(bytes);

        cOut.close();

        out.close();
    }

现在这里是如何调用/运行上面的内容：

try {
             decryptFile(new FileInputStream("encryptedFile.gpg"), new FileInputStream("PrivateKey.asc"), new FileInputStream("PublicKey.asc"), "yourKeyPassword".toCharArray());

            PGPPublicKey pubKey = readPublicKeyFromCol(new FileInputStream("PublicKey.asc"));

            encryptFile(new FileOutputStream("encryptedFileOutput.gpg"), "fileToEncrypt.txt", pubKey);




        } catch (PGPException e) {
            fail("exception: " + e.getMessage(), e.getUnderlyingException());
        }

Answer 2

第一个Google结果为this。看起来您正在尝试解密ElGamal数据，但您没有传入ElGamal密钥。

有两种简单的可能性：

您的密钥环集合有多个密钥环。
您的密钥环有子密钥。

你选择了带有ElGamal加密的DSA，所以我怀疑至少是后者：子键是由主密钥签名的; ElGamal不是签名算法（我不知道DSA和ElGamal是否可以使用相同的密钥，但通常认为使用不同的密钥用于不同的目的是一个好主意。）

我认为你想要这样的东西（同样，secretKeyRing可能应该重命名为secretKeyRingCollection）：

PGPSecretKey secretKey = secretKeyRing.getSecretKey(publicKeyEncryptedData.getKeyID());

Answer 3

我决定采用一种截然不同的方法，即完全放弃使用充气城堡，而只是简单地使用运行时过程。对我来说，这个解决方案正在发挥作用，完全消除了有关充气城堡的复杂性：

String[] gpgCommands = new String[] {
        "gpg",
        "--passphrase",
        "password",
        "--decrypt",
        "test-files/accounts.txt.gpg"
};

Process gpgProcess = Runtime.getRuntime().exec(gpgCommands);
BufferedReader gpgOutput = new BufferedReader(new InputStreamReader(gpgProcess.getInputStream()));
BufferedReader gpgError = new BufferedReader(new InputStreamReader(gpgProcess.getErrorStream()));

执行此操作后，您需要记住在进程执行时耗尽输入流，否则程序可能会挂起，具体取决于您输出的数量。看看我在这个帖子中的答案（以及Cameron Skinner和Matthew Wilson的答案，让我走上了正确的道路）以获得更多背景：Calling GnuPG in Java via a Runtime Process to encrypt and decrypt files - Decrypt always hangs

Answer 4

对于寻找替代解决方案的任何人，请参阅https://stackoverflow.com/a/42176529/7550201

final InputStream plaintextStream = BouncyGPG
           .decryptAndVerifyStream()
           .withConfig(keyringConfig)
           .andRequireSignatureFromAllKeys("sender@example.com")
           .fromEncryptedInputStream(cipherTextStream)

长话短说：Bouncycastle编程常常是很多cargo cult programming而且我写了一个库来改变它。

Answer 5

该错误消息很困难，因为它不完全准确。除了非法的密钥大小或默认参数外，该异常并不表示它可能由于加密权限检查失败而失败。这意味着您没有正确设置JCE权限。您需要安装JCE Unlimited Strength Policy。

您可以通过在jvm上设置系统属性来查看调试消息

java -Djava.security.debug=access ....

让GPG解密工作在Java（Bouncy Castle）

5 个答案: