使用 BouncyCastle java API 進行 PGP 簽名並使用 gpg4win 進行驗證不起作用

Question

我正在使用 BouncyCastle API 來簽署文件。 我正在使用 bcpg-jdk15on-164.jar、bcprov-jdk15on-164.jar 和 bcprov-ext-jdk15on-164.jar。

我正在按照他們的示例對文本文件進行簽名。 簽署文件后，當我更改文本文件中的內容並嘗試使用 Gpg4Win 進行驗證時，我仍然看到簽名有效，但沒有跡象表明無法驗證文件。

我為同一個文本文件創建了兩個簽名。 一個使用下面的代碼生成 .asc 文件，另一個使用 Gpg4Win 生成 .sig 文件。 然后我修改了文本文件。 我雙擊了每個簽名，因為在生成簽名后更改了文件，因此我希望簽名無效。 但是，BouncyCastle 生成的簽名仍然不表示文件已更改，如圖所示。 BouncyCastle 簽名顯示為綠色，而 Gpg4Win 生成的簽名顯示為紅色。 圖片：驗證 BouncyCastle 簽名與 GPG4Win 簽名

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.");
    }
}

我錯過了什么？ BouncyCastle 使用上述代碼生成的簽名是否完全有效以確保文件及其簽名的完整性？ 我已經嘗試過 BouncyCastle 的先前版本（版本 150），我也嘗試不使用 BCPGOutputStream 流，但這也無濟於事。

Answer 1

如下更改 signFile 創建了一個分離的簽名，它按預期與 Gpg4Win 一起使用：

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();
        }
    }