import org.bouncycastle.openpgp.operator.PublicKeyDataDecryptorFactory; //导入依赖的package包/类
public PublicKeyDataDecryptorFactory build(final PrivateKey privKey)
{
     return new PublicKeyDataDecryptorFactory()
     {
         public byte[] recoverSessionData(int keyAlgorithm, byte[][] secKeyData)
             throws PGPException
         {
             if (keyAlgorithm == PublicKeyAlgorithmTags.ECDH)
             {
                 throw new PGPException("ECDH requires use of PGPPrivateKey for decryption");
             }
             return decryptSessionData(keyAlgorithm, privKey, secKeyData);
         }

         public PGPDataDecryptor createDataDecryptor(boolean withIntegrityPacket, int encAlgorithm, byte[] key)
             throws PGPException
         {
             return contentHelper.createDataDecryptor(withIntegrityPacket, encAlgorithm, key);
         }
     };
}
 

import org.bouncycastle.openpgp.operator.PublicKeyDataDecryptorFactory; //导入依赖的package包/类
public PublicKeyDataDecryptorFactory build(final PrivateKey privKey)
{
     return new PublicKeyDataDecryptorFactory()
     {
         public byte[] recoverSessionData(int keyAlgorithm, BigInteger[] secKeyData)
             throws PGPException
         {
             return decryptSessionData(keyAlgorithm, privKey, secKeyData);
         }

         public PGPDataDecryptor createDataDecryptor(boolean withIntegrityPacket, int encAlgorithm, byte[] key)
             throws PGPException
         {
             return contentHelper.createDataDecryptor(withIntegrityPacket, encAlgorithm, key);
         }
     };
}
 

import org.bouncycastle.openpgp.operator.PublicKeyDataDecryptorFactory; //导入依赖的package包/类
/**
 * Builds a symmetric-encryption decryptor for the specified passphrase.
 */
protected PublicKeyDataDecryptorFactory buildPublicKeyDecryptor(
Subkey subkey) throws PGPException {
    PGPPrivateKey privateKey = subkey.getPrivateKey();
    if (privateKey == null)
        throw new PGPException("no private key for " + subkey);
    return new BcPublicKeyDataDecryptorFactory(privateKey);
}
 

import org.bouncycastle.openpgp.operator.PublicKeyDataDecryptorFactory; //导入依赖的package包/类
/**
 * Return the symmetric key algorithm required to decrypt the data protected by this object.
 *
 * @param dataDecryptorFactory   decryptor factory to use to recover the session data.
 * @return  the integer encryption algorithm code.
 * @throws PGPException if the session data cannot be recovered.
 */
public int getSymmetricAlgorithm(
    PublicKeyDataDecryptorFactory dataDecryptorFactory)
    throws PGPException
{
    byte[] plain = dataDecryptorFactory.recoverSessionData(keyData.getAlgorithm(), keyData.getEncSessionKey());

    return plain[0];
}
 

import org.bouncycastle.openpgp.operator.PublicKeyDataDecryptorFactory; //导入依赖的package包/类
@Test
public void encryptAndDecrypt() throws Exception {
	// both keys have property encryptionKey==true
	final String[] keyIds = {
			"d7a92a24aa97ddbd", // master-key
			"a58da7d810b74edf" // sub-key
	};

	for (final String keyId : keyIds) {
		final PGPDataEncryptorBuilder encryptorBuilder = new BcPGPDataEncryptorBuilder(SymmetricKeyAlgorithmTags.TWOFISH);
		final PGPEncryptedDataGenerator encryptedDataGenerator = new PGPEncryptedDataGenerator(encryptorBuilder);
		final PGPKeyEncryptionMethodGenerator keyEncryptionMethodGenerator = new BcPublicKeyKeyEncryptionMethodGenerator(
				getPgpPublicKeyOrFail(bytesToLong(decodeHexStr(keyId))));

		encryptedDataGenerator.addMethod(keyEncryptionMethodGenerator);

		final byte[] plain = new byte[1 + random.nextInt(1024 * 1024)];
		random.nextBytes(plain);

		final File encryptedFile = File.createTempFile("encrypted_", ".tmp");
		try (final OutputStream encryptedOut = new FileOutputStream(encryptedFile);) {
			try (final OutputStream plainOut = encryptedDataGenerator.open(encryptedOut, new byte[1024 * 16]);) {
				plainOut.write(plain);
			}
		}

		final byte[] decrypted;
		try (InputStream in = new FileInputStream(encryptedFile)) {
			final PGPEncryptedDataList encryptedDataList = new PGPEncryptedDataList(new BCPGInputStream(in));
			final Iterator<?> encryptedDataObjects = encryptedDataList.getEncryptedDataObjects();
			assertThat(encryptedDataObjects.hasNext()).isTrue();
			final PGPPublicKeyEncryptedData encryptedData = (PGPPublicKeyEncryptedData) encryptedDataObjects.next();
			assertThat(encryptedDataObjects.hasNext()).isFalse();

			final PublicKeyDataDecryptorFactory dataDecryptorFactory = new BcPublicKeyDataDecryptorFactory(
					getPgpPrivateKeyOrFail(encryptedData.getKeyID(), "test12345".toCharArray()));

			try (InputStream plainIn = encryptedData.getDataStream(dataDecryptorFactory);) {
				final ByteArrayOutputStream out = new ByteArrayOutputStream();
				transferStreamData(plainIn, out);
				decrypted = out.toByteArray();
			}
		}

		assertThat(decrypted).isEqualTo(plain);

		encryptedFile.delete(); // delete it, if this test did not fail
	}
}