java - "Wrong algorithm"尝试在 Java 中解密时出错

Question

我首先要描述我遇到的问题，然后介绍我正在尝试做的事情的一些背景。最后，我将粘贴一些相关的代码片段。

我正在尝试使用 https://stackoverflow.com/a/992413/171993 中指定的方法实现 key 加密/解密.如果我按原样使用该示例，它会起作用(尽管我确实注意到我需要重新实例化 Cipher 类，否则解密会产生垃圾)。但是，在我的实现中出现以下异常:

java.security.InvalidKeyException: Wrong algorithm: AES or Rijndael required
    at com.sun.crypto.provider.AESCrypt.init(AESCrypt.java:77)
    at com.sun.crypto.provider.CipherBlockChaining.init(CipherBlockChaining.java:91)
    at com.sun.crypto.provider.CipherCore.init(CipherCore.java:469)
    at com.sun.crypto.provider.AESCipher.engineInit(AESCipher.java:217)
    at javax.crypto.Cipher.implInit(Cipher.java:790)
    at javax.crypto.Cipher.chooseProvider(Cipher.java:848)
    at javax.crypto.Cipher.init(Cipher.java:1347)
    at javax.crypto.Cipher.init(Cipher.java:1281)
    at securitytest.SecurityManager.getCipher(SecurityManager.java:175)
    at securitytest.SecurityManager.decryptSecretKey(SecurityManager.java:379)
    at securitytest.SecurityManager.<init>(SecurityManager.java:82)
    at securitytest.Test.main(Test.java:44)

为了解决这个明显的问题，是的，我确实使用了相同的算法:事实上，我将 AES/CBC/PKCS5Padding 分配给一个常量，并使用它来实例化 Cipher 加密和解密类。我也尝试过仅使用 AES 实例化 Cipher 进行解密，但这也不起作用。

我想做的是使用 AES/CBC/PKCS5Padding 密码保护 key 。我生成一个随机盐和初始化 vector 。加密 key 后，我将初始化 vector (一个字节数组)附加到加密值(也是一个字节数组，创建一个新数组)。然后，我在 Base64 中对该值进行编码，并将其与 salt 一起存储在 Sqlite 数据库中(为了简单起见，我将其存储为以逗号分隔的值字符串)。但是，当我尝试解密时，出现上述异常。我可以验证在调用加密方法之后和解密方法之前，以下值完全相同(转换为 Base64 以便打印出来):

1. 盐
2. 初始化 vector
3. 加密 key (即密文)

我已经尝试过 Java 6 和 7:两者的结果相同。我还排除了无限强度管辖政策文件的问题。事实上，如果我用另一种算法替换“AES”并相应地调整盐的长度(例如，IV 长度为 8 的“Blowfish”，它会产生 java.security.InvalidKeyException:错误的算法:需要河豚)。

Google 无法帮助我解决这个问题。如果有人能对此有所了解，我将不胜感激。

以下是一些代码片段(抱歉，有点粗糙):

private static final int INIT_VECTOR_LENGTH = 16;
private static final int PRIVATE_KEY_LENGTH = 128;
private static final int SALT_LENGTH = 16;
private static final int PBE_KEYSPEC_ITERATIONS = 65536;

private static final String CIPHER_ALGORITHM = "AES";
private static final String CIPHER_ALGORITHM_MODE = "CBC";
private static final String CIPHER_ALGORITHM_PADDING = "PKCS5Padding";
private static final String DIGEST = "SHA1";
private static final String PLAINTEXT_ENCODING = "UTF8";
private static final String PRNG = DIGEST + "PRNG";
private static final String SECRET_KEY_FACTORY = "PBKDF2WithHmac" + DIGEST;

private static final String CIPHER = CIPHER_ALGORITHM + "/" + CIPHER_ALGORITHM_MODE + "/" + CIPHER_ALGORITHM_PADDING;

private IvParameterSpec ivSpec;
private final BASE64Encoder encoder = new BASE64Encoder();
private final BASE64Decoder decoder = new BASE64Decoder();

private Cipher getCipher(SecretKey key, int mode) {

    Cipher cipher = null;

    try {
        cipher = Cipher.getInstance(CIPHER);
    }
    catch (NoSuchAlgorithmException e) {System.err.println(System.err.println(e.getMessage());}
    catch (NoSuchPaddingException e) {System.err.println(e.getMessage());}

    try {
        if (mode == Cipher.ENCRYPT_MODE) {
            cipher.init(mode, key);
            AlgorithmParameters params = cipher.getParameters();
            ivSpec = params.getParameterSpec(IvParameterSpec.class);
        }
        else {
            /* This is my point-of-failure. */
            cipher.init(mode, key, ivSpec);
        }
    }
    catch (InvalidKeyException e) {System.err.println(e.getMessage());}
    catch (InvalidAlgorithmParameterException e) {System.err.println(e.getMessage());}
    catch (InvalidParameterSpecException e) {System.err.println(e.getMessage());}

    return cipher;

}

private SecurityData.Secrets generateSecrets(SecretKey decryptedKey, byte[] salt, String passphrase) {

    /* Generate a new key for encrypting the secret key. */
    byte[] raw = null;
    PBEKey key = null;
    PBEKeySpec password = new PBEKeySpec(passphrase.toCharArray(), salt, PBE_KEYSPEC_ITERATIONS, PRIVATE_KEY_LENGTH);
    SecretKeyFactory factory = null;
    byte[] initVector = null;
    byte[] secretKeyBytes = decryptedKey.getEncoded();

    try {
        factory = SecretKeyFactory.getInstance(SECRET_KEY_FACTORY);
        key = (PBEKey) factory.generateSecret(password);
    }
    catch (NoSuchAlgorithmException e) {System.err.println(e.getMessage());}
    catch (InvalidKeySpecException e) {System.err.println(e.getMessage());}

    SecretKeySpec newKey = new SecretKeySpec(key.getEncoded(), CIPHER_ALGORITHM);

    /* Encrypt the secret key. */
    IvParameterSpec ivSpec = new IvParameterSpec(initVector);
    Cipher cipher = getCipher(newKey, ivSpec, Cipher.ENCRYPT_MODE);

    try {
        raw = cipher.doFinal(secretKeyBytes);
    }
    catch (IllegalBlockSizeException e) {System.err.println(e.getMessage());}
    catch (BadPaddingException e) {System.err.println(e.getMessage());}

    return new SecurityData.Secrets(encoder.encode(concatByteArrays(initVector, raw)), joinByteArray(salt));

}

private SecretKey decryptSecretKey(String encryptedKey, String salt, String passphrase) {

    /* Get initialisation vector. */
    byte[] raw = null, decoded = null, initVector = new byte[INIT_VECTOR_LENGTH];
    try {
        decoded = decoder.decodeBuffer(encryptedKey);
    } catch (IOException e) {System.err.println(e.getMessage());}
    System.arraycopy(decoded, 0, initVector, 0, INIT_VECTOR_LENGTH);
    raw = new byte[decoded.length-INIT_VECTOR_LENGTH];
    System.arraycopy(decoded, INIT_VECTOR_LENGTH, raw, 0, decoded.length-INIT_VECTOR_LENGTH);
    IvParameterSpec ivSpec = new IvParameterSpec(initVector);

    /* Generate the key. */
    byte[] rawSalt = splitByteArrayString(salt);
    PBEKeySpec password = new PBEKeySpec(passphrase.toCharArray(), rawSalt, PBE_KEYSPEC_ITERATIONS, PRIVATE_KEY_LENGTH);
    SecretKeyFactory factory = null;
    PBEKey key = null;
    try {
        factory = SecretKeyFactory.getInstance(SECRET_KEY_FACTORY);
        key = (PBEKey) factory.generateSecret(password);
    }
    catch (NoSuchAlgorithmException e) {System.err.println(e.getMessage());}
    catch (InvalidKeySpecException e) {System.err.println(e.getMessage());}

    Cipher cipher = getCipher(key, Cipher.DECRYPT_MODE);

    /* Decrypt the message. */
    byte[] stringBytes = null;
    try {
        stringBytes = cipher.doFinal(raw);
    }
    catch (IllegalBlockSizeException e) {System.err.println(e.getMessage());}
    catch (BadPaddingException e) {System.err.println(e.getMessage());}

    /* Converts the decoded message to a String. */
    String clear = null;
    try {
        clear = new String(stringBytes, PLAINTEXT_ENCODING);
    }
    catch (UnsupportedEncodingException e) {System.err.println(e.getMessage());}

    return new SecretKeySpec(clear.getBytes(), CIPHER_ALGORITHM);

}

Answer 1

SecretKey 对象需要从其 getAlgorithm() 方法返回“AES”。这就是该示例具有以下步骤的原因:

SecretKey tmp = factory.generateSecret(spec);
SecretKey secret = new SecretKeySpec(tmp.getEncoded(), "AES");