使用 BouncyCastle java API 进行 PGP 签名并使用 gpg4win 进行验证不起作用

Question

我正在使用 BouncyCastle API 对文件进行签名。我正在使用 bcpg-jdk15on-164.jar、bcprov-jdk15on-164.jar 和 bcprov-ext-jdk15on-164.jar。

我正在按照他们的示例对文本文件进行签名。签署文件后，当我更改文本文件中的内容并尝试使用 Gpg4Win 进行验证时，我仍然看到签名有效，但没有迹象表明文件无法验证。

我为同一个文本文件创建了两个签名。一个使用下面的代码生成 .asc 文件，另一个使用 Gpg4Win 生成 .sig 文件。然后我修改了文本文件。我双击了每个签名，我希望签名变得无效，因为在生成签名后文件被更改。然而，BouncyCastle 生成的签名仍然不表示文件已被更改，如图所示。 BouncyCastle 签名显示为绿色，而 Gpg4Win 生成的签名显示为红色。 图片：Verifying BouncyCastle signature vs GPG4Win signature

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.Security;
import java.security.SignatureException;
import java.util.Iterator;

import org.bouncycastle.bcpg.ArmoredOutputStream;
import org.bouncycastle.bcpg.BCPGOutputStream;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.openpgp.PGPCompressedData;
import org.bouncycastle.openpgp.PGPCompressedDataGenerator;
import org.bouncycastle.openpgp.PGPException;
import org.bouncycastle.openpgp.PGPLiteralData;
import org.bouncycastle.openpgp.PGPLiteralDataGenerator;
import org.bouncycastle.openpgp.PGPOnePassSignature;
import org.bouncycastle.openpgp.PGPOnePassSignatureList;
import org.bouncycastle.openpgp.PGPPrivateKey;
import org.bouncycastle.openpgp.PGPPublicKey;
import org.bouncycastle.openpgp.PGPPublicKeyRingCollection;
import org.bouncycastle.openpgp.PGPSecretKey;
import org.bouncycastle.openpgp.PGPSecretKeyRing;
import org.bouncycastle.openpgp.PGPSecretKeyRingCollection;
import org.bouncycastle.openpgp.PGPSignature;
import org.bouncycastle.openpgp.PGPSignatureGenerator;
import org.bouncycastle.openpgp.PGPSignatureList;
import org.bouncycastle.openpgp.PGPSignatureSubpacketGenerator;
import org.bouncycastle.openpgp.PGPUtil;
import org.bouncycastle.openpgp.operator.KeyFingerPrintCalculator;
import org.bouncycastle.openpgp.operator.jcajce.JcaKeyFingerprintCalculator;
import org.bouncycastle.openpgp.operator.jcajce.JcaPGPContentSignerBuilder;
import org.bouncycastle.openpgp.operator.jcajce.JcaPGPContentVerifierBuilderProvider;
import org.bouncycastle.openpgp.operator.jcajce.JcePBESecretKeyDecryptorBuilder;

/**
 * A simple utility class that signs and verifies files.
 * <p>
 * To sign a file: SignedFileProcessor -s [-a] fileName secretKey passPhrase.<br>
 * If -a is specified the output file will be "ascii-armored".
 * <p>
 * To decrypt: SignedFileProcessor -v fileName publicKeyFile.
 * <p>
 * <b>Note</b>: this example will silently overwrite files, nor does it pay any attention to
 * the specification of "_CONSOLE" in the filename. It also expects that a single pass phrase
 * will have been used.
 * <p>
 * <b>Note</b>: the example also makes use of PGP compression. If you are having difficulty getting it
 * to interoperate with other PGP programs try removing the use of compression first.
 */
public class SignedFileProcessor
{

    /**
     * Generate an encapsulated signed file.
     * 
     * @param fileName
     * @param keyIn
     * @param out
     * @param pass
     * @param armor
     * @throws IOException
     * @throws NoSuchAlgorithmException
     * @throws NoSuchProviderException
     * @throws PGPException
     * @throws SignatureException
     */
    private static void signFile(
        String          fileName,
        InputStream     keyIn,
        OutputStream    out,
        char[]          pass,
        boolean         armor)
        throws IOException, NoSuchAlgorithmException, NoSuchProviderException, PGPException, SignatureException
    {
        if (armor)
        {
            out = new ArmoredOutputStream(out);
        }

        PGPSecretKey                pgpSec = readSecretKey(keyIn);
        PGPPrivateKey               pgpPrivKey = pgpSec.extractPrivateKey(new JcePBESecretKeyDecryptorBuilder().setProvider("BC").build(pass));
        PGPSignatureGenerator       sGen = new PGPSignatureGenerator(new JcaPGPContentSignerBuilder(pgpSec.getPublicKey().getAlgorithm(), PGPUtil.SHA1).setProvider("BC"));

        sGen.init(PGPSignature.BINARY_DOCUMENT, pgpPrivKey);

        Iterator    it = pgpSec.getPublicKey().getUserIDs();
        if (it.hasNext())
        {
            PGPSignatureSubpacketGenerator  spGen = new PGPSignatureSubpacketGenerator();

            spGen.setSignerUserID(false, (String)it.next());
            sGen.setHashedSubpackets(spGen.generate());
        }

        PGPCompressedDataGenerator  cGen = new PGPCompressedDataGenerator(PGPCompressedData.ZLIB);

        BCPGOutputStream            bOut = new BCPGOutputStream(cGen.open(out));

        sGen.generateOnePassVersion(false).encode(bOut);

        File                        file = new File(fileName);
        PGPLiteralDataGenerator     lGen = new PGPLiteralDataGenerator();
        OutputStream                lOut = lGen.open(bOut, PGPLiteralData.BINARY, file);
        FileInputStream             fIn = new FileInputStream(file);
        int                         ch;

        while ((ch = fIn.read()) >= 0)
        {
            lOut.write(ch);
            sGen.update((byte)ch);
        }

        lGen.close();

        sGen.generate().encode(bOut);

        cGen.close();

        if (armor)
        {
            out.close();
        }
    }

    public static void main(
        String[] args)
        throws Exception
    {
        Security.addProvider(new BouncyCastleProvider());
        String rootFolder = System.getProperty("user.dir"); 
        String fileName = rootFolder + "\\files\\helloworld.txt";
        FileInputStream     keyIn = new FileInputStream(rootFolder + "\\files\\sign-and-encrypt_priv.asc");
        FileOutputStream    out = new FileOutputStream(fileName + ".asc");


        signFile(fileName, keyIn, out, "hongkong".toCharArray(), true);
        System.out.println("DONE");
    }

    /**
     * A simple routine that opens a key ring file and loads the first available key
     * suitable for signature generation.
     * 
     * @param input stream to read the secret key ring collection from.
     * @return a secret key.
     * @throws IOException on a problem with using the input stream.
     * @throws PGPException if there is an issue parsing the input stream.
     */
    static PGPSecretKey readSecretKey(InputStream input) throws IOException, PGPException
    {
        PGPSecretKeyRingCollection pgpSec = new PGPSecretKeyRingCollection(
            PGPUtil.getDecoderStream(input), new JcaKeyFingerprintCalculator());

        //
        // we just loop through the collection till we find a key suitable for encryption, in the real
        // world you would probably want to be a bit smarter about this.
        //

        Iterator keyRingIter = pgpSec.getKeyRings();
        while (keyRingIter.hasNext())
        {
            PGPSecretKeyRing keyRing = (PGPSecretKeyRing)keyRingIter.next();

            Iterator keyIter = keyRing.getSecretKeys();
            while (keyIter.hasNext())
            {
                PGPSecretKey key = (PGPSecretKey)keyIter.next();

                if (key.isSigningKey())
                {
                    return key;
                }
            }
        }

        throw new IllegalArgumentException("Can't find signing key in key ring.");
    }
}

我错过了什么？ BouncyCastle 使用上面的代码生成的签名是否完全有效，以确保文件及其签名的完整性？我已经尝试过 BouncyCastle 的早期版本（版本 150），我也尝试过不使用 BCPGOutputStream 流，但这也无济于事。

Answer 1

更改 signFile 如下创建了一个分离的签名，它可以与 Gpg4Win 一起正常工作：

private static void signFile(
        String          fileName,
        InputStream     keyIn,
        OutputStream    out,
        char[]          pass,
        boolean         armor)
        throws IOException, NoSuchAlgorithmException, NoSuchProviderException, PGPException, SignatureException
    {
        if (armor)
        {
            out = new ArmoredOutputStream(out);
        }

        PGPSecretKey             pgpSec = readSecretKey(keyIn);
        PGPPrivateKey            pgpPrivKey = pgpSec.extractPrivateKey(new JcePBESecretKeyDecryptorBuilder().setProvider("BC").build(pass));
        PGPSignatureGenerator    sGen = new PGPSignatureGenerator(new JcaPGPContentSignerBuilder(pgpSec.getPublicKey().getAlgorithm(), PGPUtil.SHA1).setProvider("BC"));

        sGen.init(PGPSignature.BINARY_DOCUMENT, pgpPrivKey);

        BCPGOutputStream         bOut = new BCPGOutputStream(out);

        InputStream              fIn = new BufferedInputStream(new FileInputStream(fileName));

        int ch;
        while ((ch = fIn.read()) >= 0)
        {
            sGen.update((byte)ch);
        }

        fIn.close();

        sGen.generate().encode(bOut);

        if (armor)
        {
            out.close();
        }
    }