AES-Java中的简单加密，使用openssl解密

Question

我正在尝试使用Java Cryto在Java中进行简单的AES加密，然后可以使用OpenSSL在ObjectiveC中对其进行解密。

因为我没有在ObjectiveC方面进行操作，所以我想使用openSSL命令行确保它可以正常工作，但是我总是会收到“错误的魔术数字”

这是我的Java代码

public class EncryptionUtils {

private static final String AES_CIPHER_METHOD = "AES";
private static final int AES_KEY_SIZE = 128;

public static byte[] generateAesKey() throws NoSuchAlgorithmException {
    KeyGenerator keyGenerator = KeyGenerator.getInstance(AES_CIPHER_METHOD);
    keyGenerator.init(AES_KEY_SIZE);
    SecretKey key = keyGenerator.generateKey();
    return key.getEncoded();
}

public static SecretKeySpec createAesKeySpec(byte[] aesKey) {
    return new SecretKeySpec(aesKey, AES_CIPHER_METHOD);
}

public static void aesEncryptFile(File in, File out, SecretKeySpec aesKeySpec) throws InvalidKeyException, NoSuchAlgorithmException, NoSuchPaddingException, IOException {
    Cipher aesCipher = Cipher.getInstance(AES_CIPHER_METHOD);
    aesCipher.init(Cipher.ENCRYPT_MODE, aesKeySpec);
    InputStream inputStream = new FileInputStream(in);
    try {
        OutputStream outputStream = new CipherOutputStream(new FileOutputStream(out), aesCipher);
        try {
            IOUtils.copy(inputStream , outputStream);
        } finally {
            outputStream.close();
        }
    } finally {
        inputStream.close();
    }
}
}


//testcode
@Test
public void testAesEncryptFile() throws IOException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException, NoSuchAlgorithmException, NoSuchPaddingException {
    byte[] aesKey = EncryptionUtils.generateAesKey();
    SecretKeySpec aesKeySpec = EncryptionUtils.createAesKeySpec(aesKey);
    EncryptionUtils.aesEncryptFile(new File("C:\\test\\test.txt"), new File("C:\\test\\test-encrypted.txt"), aesKeySpec);

    FileOutputStream outputStream = new FileOutputStream("C:\\test\\aes.key");
    outputStream.write(aesKey);
    outputStream.close();
}

@Test
public void testAesDecryptFile() throws IOException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException, NoSuchAlgorithmException, NoSuchPaddingException {
    FileInputStream keyFis = new FileInputStream("C:\\test\\aes.key");
    ByteArrayOutputStream keyBaos = new ByteArrayOutputStream();
    IOUtils.copy(keyFis, keyBaos);

    SecretKeySpec keySpec = new SecretKeySpec(keyBaos.toByteArray(), "AES");
    Cipher cipher = Cipher.getInstance("AES");
    cipher.init(Cipher.DECRYPT_MODE, keySpec);

    FileInputStream fileInputStream = new FileInputStream("C:\\test\\test-encrypted.txt");
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    IOUtils.copy(fileInputStream, baos);

    byte[] decrypted = cipher.doFinal(baos.toByteArray());
    FileOutputStream outputStream = new FileOutputStream("C:\\test\\test-decrypted.txt");
    outputStream.write(decrypted);
    outputStream.close();

}

现在可以按预期运行，文件“ test-encrypted.txt”确实已加密，并且“ test-decrypted.txt” ==“ test.txt”

然后，我尝试使用OpenSSL在命令行上运行解密

openssl enc -d -aes-128-ecb -in test-encrypted.txt -k aes.key

但是，这总是给我

bad magic number

从我可以看到，Java中的使用算法“ AES”默认情况下使用“ ECB”模式，因此上述方法应该可以工作。我究竟做错了什么。

Answer 1

问题确实是由于OpenSSL从密码计算出的密钥所致。

原因很可能是OpenSSL拥有自己的算法来从密码派生密钥EVP_BytesToKey，这与Java的算法不同。

我发现的唯一解决方案是使用该算法的Java重新实现：

private static final int KEY_LENGTH = 32;    

private byte[] deriveKey(String encryptionPassword, byte[] salt) throws NoSuchAlgorithmException {
    final byte[] passAndSalt = ArrayUtils.addAll(encryptionPassword.getBytes(), salt);
    byte[] hash = new byte[0];
    byte[] keyAndIv = new byte[0];
    for (int i = 0; i < 3 && keyAndIv.length < KEY_LENGTH; i++) {
        final byte[] dataToHash = ArrayUtils.addAll(hash, passAndSalt);
        final MessageDigest md = MessageDigest.getInstance("SHA-256");
        hash = md.digest(dataToHash);
        keyAndIv = ArrayUtils.addAll(keyAndIv, hash);
    }
    return Arrays.copyOfRange(keyAndIv, 0, KEY_LENGTH);
}
ArrayUtils 是Apache Commons库的一部分。

完整用法：

IvParameterSpec initializationVectorSpec = new IvParameterSpec(
                Hex.decodeHex(encryptionInitializationVector.toCharArray()));

cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
byte[] salt = new SecureRandom().generateSeed(8);
byte[] key = deriveKey(encryptionPassword, salt);
Key keySpec = new SecretKeySpec(key, "AES");
cipher.init(Cipher.ENCRYPT_MODE, keySpec, initializationVectorSpec);

byte[] rawEncryptedInput = cipher.doFinal(input.getBytes());
byte[] encryptedInputWithPrependedSalt = ArrayUtils.addAll(ArrayUtils.addAll(
                "Salted__".getBytes(), salt), rawEncryptedInput);
return Base64.getEncoder()
                .encodeToString(encryptedInputWithPrependedSalt);