Java：使用 Bouncy Castle 进行 PGP 加密

我正在尝试使用 PGP 实现加密，并且我的加密方法成功加密了输入字符串，但是当我尝试解密它以验证加密是否正确完成时，该字符串不会被解密。

我尝试了两种方法：

第一种方法使用文件输出流编写加密字符串和第二种方法使用字节数组输出流. 文件输出流创建一个文件，我可以使用 Kleopatra 对其进行解密。然而我的要求是只获取一个加密的字符串（不写入文件中）。因此，当我尝试解密加密字符串（使用后收到字节数组输出流）它不工作。我尝试复制字符串并通过 Kleopatra 中的工具>>剪贴板解密它，但解密/验证选项被禁用。我尝试通过 FileWriter 类手动在文件上写入字符串，但解密失败并出现以下错误文件包含证书且无法解密或验证。

我假设只有由 OutputStream 直接创建的文件才能成功解密。 但我必须真正检查加密的字符串。

任何帮助将不胜感激。

以下完整示例取自《Java Cryptography：Tools and Techniques by David Hook & Jon Eaves》一书的源代码。 包含所有示例的完整源代码可在此处获取：https://www.bouncycastle.org/java-crypto-tools-src.zip https://www.bouncycastle.org/java-crypto-tools-src.zip

这些示例展示了使用 El Gamal 或椭圆曲线创建私钥/公钥以及使用 AES-256 加密。 在 ecExample-method 中，我添加了两行，将加密字符串保存到文件“pgp-encrypted-string.dat”中，然后 重新加载数据以解密文件并显示解密的字符串。

import org.bouncycastle.bcpg.SymmetricKeyAlgorithmTags;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.openpgp.*;
import org.bouncycastle.openpgp.jcajce.JcaPGPObjectFactory;
import org.bouncycastle.openpgp.operator.PublicKeyDataDecryptorFactory;
import org.bouncycastle.openpgp.operator.jcajce.JcaPGPKeyPair;
import org.bouncycastle.openpgp.operator.jcajce.JcePGPDataEncryptorBuilder;
import org.bouncycastle.openpgp.operator.jcajce.JcePublicKeyDataDecryptorFactoryBuilder;
import org.bouncycastle.openpgp.operator.jcajce.JcePublicKeyKeyEncryptionMethodGenerator;
import org.bouncycastle.util.Strings;
import org.bouncycastle.util.io.Streams;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.SecureRandom;
import java.security.Security;
import java.security.spec.ECGenParameterSpec;
import java.util.Date;

public class PGPEncryptionExampleForSO
{
     /**
     * Create an encrypted data blob using an AES-256 session key and the
     * passed in public key.
     *
     * @param encryptionKey the public key to use.
     * @param data the data to be encrypted.
     * @return a PGP binary encoded version of the encrypted data.
     */
    public static byte[] createEncryptedData(
        PGPPublicKey encryptionKey,
        byte[] data)
        throws PGPException, IOException
    {
        PGPEncryptedDataGenerator encGen = new PGPEncryptedDataGenerator(
            new JcePGPDataEncryptorBuilder(SymmetricKeyAlgorithmTags.AES_256)
                .setWithIntegrityPacket(true)
                .setSecureRandom(new SecureRandom()).setProvider("BC"));
        encGen.addMethod(
            new JcePublicKeyKeyEncryptionMethodGenerator(encryptionKey)
                .setProvider("BC"));
        ByteArrayOutputStream encOut = new ByteArrayOutputStream();
        // create an indefinite length encrypted stream
        OutputStream cOut = encGen.open(encOut, new byte[4096]);
        // write out the literal data
        PGPLiteralDataGenerator lData = new PGPLiteralDataGenerator();
        OutputStream pOut = lData.open(
            cOut, PGPLiteralData.BINARY,
            PGPLiteralData.CONSOLE, data.length, new Date());
        pOut.write(data);
        pOut.close();
        // finish the encryption
        cOut.close();
        return encOut.toByteArray();
    }

    /**
     * Extract the plain text data from the passed in encoding of PGP
     * encrypted data. The routine assumes the passed in private key
     * is the one that matches the first encrypted data object in the
     * encoding.
     *
     * @param privateKey the private key to decrypt the session key with.
     * @param pgpEncryptedData the encoding of the PGP encrypted data.
     * @return a byte array containing the decrypted data.
     */
    public static byte[] extractPlainTextData(
        PGPPrivateKey privateKey,
        byte[] pgpEncryptedData)
        throws PGPException, IOException
    {
        PGPObjectFactory pgpFact = new JcaPGPObjectFactory(pgpEncryptedData);
        PGPEncryptedDataList encList = (PGPEncryptedDataList)pgpFact.nextObject();
        // find the matching public key encrypted data packet.
        PGPPublicKeyEncryptedData encData = null;
        for (PGPEncryptedData pgpEnc: encList)
        {
            PGPPublicKeyEncryptedData pkEnc
                = (PGPPublicKeyEncryptedData)pgpEnc;
            if (pkEnc.getKeyID() == privateKey.getKeyID())
            {
                encData = pkEnc;
                break;
            }
        }
        if (encData == null)
        {
            throw new IllegalStateException("matching encrypted data not found");
        }
        // build decryptor factory
        PublicKeyDataDecryptorFactory dataDecryptorFactory =
            new JcePublicKeyDataDecryptorFactoryBuilder()
                .setProvider("BC")
                .build(privateKey);
        InputStream clear = encData.getDataStream(dataDecryptorFactory);
        byte[] literalData = Streams.readAll(clear);
        clear.close();
        // check data decrypts okay
        if (encData.verify())
        {
            // parse out literal data
            PGPObjectFactory litFact = new JcaPGPObjectFactory(literalData);
            PGPLiteralData litData = (PGPLiteralData)litFact.nextObject();
            byte[] data = Streams.readAll(litData.getInputStream());
            return data;
        }
        throw new IllegalStateException("modification check failed");
    }

    private static void elgamalExample()
        throws Exception
    {
        byte[] msg = Strings.toByteArray("Hello, world!");
        KeyPairGenerator kpGen = KeyPairGenerator.getInstance("DH", "BC");
        kpGen.initialize(2048);
        KeyPair kp = kpGen.generateKeyPair();
        PGPKeyPair elgKp = new JcaPGPKeyPair(
            PGPPublicKey.ELGAMAL_ENCRYPT, kp, new Date());
        byte[] encData = createEncryptedData(elgKp.getPublicKey(), msg);
        byte[] decData = extractPlainTextData(elgKp.getPrivateKey(), encData);
        System.out.println("elgamal encryption msg length: " + msg.length + " enc.length: " + encData.length + " dec.length: " + decData.length);
        System.out.println(Strings.fromByteArray(decData));
    }

    private static void ecExample()
        throws Exception
    {
        byte[] msg = Strings.toByteArray("Hello, world!");
        KeyPairGenerator kpGen = KeyPairGenerator.getInstance("EC", "BC");
        kpGen.initialize(new ECGenParameterSpec("P-256"));
        KeyPair kp = kpGen.generateKeyPair();
        PGPKeyPair ecdhKp = new JcaPGPKeyPair(PGPPublicKey.ECDH, kp, new Date());
        byte[] encData = createEncryptedData(ecdhKp.getPublicKey(), msg);
        // save encrypted string
        Files.write(Paths.get("pgp-encrypted-string.dat"), encData);
        // load encrypted string
        byte[] encDataLoad = Files.readAllBytes(Paths.get("pgp-encrypted-string.dat"));
        byte[] decData = extractPlainTextData(ecdhKp.getPrivateKey(), encDataLoad);
        System.out.println("ec encryption msg length: " + msg.length + " enc.length: " + encData.length + " dec.length: " + decData.length);
        System.out.println(Strings.fromByteArray(decData));
    }

    public static void main(String[] args)
        throws Exception
    {
        Security.addProvider(new BouncyCastleProvider());
        // you need the two files bcpg-jdk15on-165.jar and bcprov-jdk15to18-165.jar to run the example
        System.out.println("Example from Java Cryptography: Tools and Techniques by David Hook & Jon Eaves");
        System.out.println("get source files: https://www.bouncycastle.org/java-crypto-tools-src.zip");
        elgamalExample();
        ecExample();
    }
}

这是简短的输出：

Example from Java Cryptography: Tools and Techniques by David Hook & Jon Eaves
get source files: https://www.bouncycastle.org/java-crypto-tools-src.zip
elgamal encryption msg length: 13 enc.length: 601 dec.length: 13
Hello, world!
ec encryption msg length: 13 enc.length: 200 dec.length: 13
Hello, world!

Added:据我现在了解，你有一个像这样的字符串

This string needs an encryption

并且您想使用 rsa pgp 公钥对其进行加密：

-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: BCPG v1.65

mI0EXr/nDgEEAKhB6ufAB954aBIlNjPCsryzUVLu0qkC/1RtnFHf+J6IVegV8Wi7
28V074inQcw6o6FTLtFTaLRP4+3eXNATdjGSjrvcP7k+nu50vydugHv43fPuCiZ7
6gbbMTE9gPiLPA2pS+SmQJnr9hOrD5rzwYP1yNNIsRJ9qmU5NeZyu+szABEBAAG0
DHRlc3RpZGVudGl0eYicBBABAgAGBQJev+cOAAoJEPBDuyqTbz/gY0YD/R+gDkfe
qPgNuk6iI2wLSGEeZRXr6Ru1cyG73CRvz7BjCpwWx039AdQzP9gkeo6MEj8Z0c73
obqEP8NtvvOcwC7+/QiGLTR2mgCsNhk54+iCGsvNbkpkr/rRoYZGyvb+rxui0A61
DCB1w5hdnyMg2OglFNrkaPfpNjMsTebfF5eS
=h1+m
-----END PGP PUBLIC KEY BLOCK-----

并获取加密后的字符串

-----BEGIN PGP MESSAGE-----
Version: BCPG v1.65

hIwD8EO7KpNvP+ABA/9JkOE9PDyS/kr/lZ1Uz+NCSe1JiNcKCXjbsUbvP8CT7Tf1
cKlgzIz1mQjdpkBtVpVhEnEjmUzFy2UCRKr4b4Wx7/1UL+370CICW5HgMoi5TgTg
MYRy5I9Uba/+JxcusjWB1JJHP4ofULziXRKLWAoSPLlglZDzSmV88hNo19rl39JZ
AbMhIS2edM9hHICefL/Yaiq90hGjKMRReVopu2tPUjNLGYP7QABAvWb3WQJMZoYT
HEsyjHxeyYQylAdYB7pWQA0++Z803iclvM3skN8FBt64ebDkqfxgbhs=
=je0r
-----END PGP MESSAGE-----

现在您想使用 Kleoptatra 在线解密此消息（例如https://sela.io/pgp-en/ https://sela.io/pgp-en/）或在 Java 中使用 RSA pgp 私钥和密码 123456：

-----BEGIN PGP PRIVATE KEY BLOCK-----
Version: BCPG v1.65
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=y/tQ
-----END PGP PRIVATE KEY BLOCK-----

并获取解密后的字符串：

This string needs an encryption

幸运的是，要使用 Java 进行加密/解密，BouncyCastle Github-Repo 中提供了示例文件：https://github.com/bcgit/bc-java/blob/master/pg/src/main/java/org/bouncycastle/openpgp/examples/ https://github.com/bcgit/bc-java/blob/master/pg/src/main/java/org/bouncycastle/openpgp/examples/。您可能需要使用 RSA (RSAKeyPairGenerator.java) 或 ElGamal 创建新的 PGP 密钥对 （DSAElGamalKeyRingGenerator.java）。使用生成的密钥，您可以使用 KeyBasedFileProcessor.java 和必要的 PGPExampleUtil.java 进行加密或解密。

我使用“-a testidentity 123456”作为参数创建了 RSA 密钥文件，加密是使用“-e -ai plaintext.txt rsa_pub.asc”完成的，解密是使用“-d plaintext.txt.asc rsa_secret.asc 123456 ”。