Question

public static String doGenerate() {
    int val = 10000000;
    Random r = new Random();
    int gen = r.nextInt(89999999);
    int gen1 = r.nextInt(89999999);
    gen = val + gen;
    gen1 = val + gen1;
    String reply = gen + "" + gen1;
    return reply;
}

这是我用来生成下面给出的AES算法所需的密钥的方法。

public static void decryptFile(String keyString, String fileName){
    try {
        KeyGenerator kgen = KeyGenerator.getInstance("AES");
        kgen.init(128);
        SecretKey key = (SecretKey) new SecretKeySpec(
            keyString.getBytes(), "AES");// kgen.generateKey();

        AESEncrypter encrypter = new AESEncrypter(key);

        encrypter.decrypt(new FileInputStream(
            new java.io.File("").getCanonicalFile() +
            File.separator + "Received"+
            File.separator + fileName),
            new FileOutputStream(new java.io.File("").getCanonicalFile() +
            File.separator + "Decrypted" + 
            File.separator + fileName));
    } catch (Exception e) {
        e.printStackTrace();
    }
}

这是AESEncrypter方法。

  public AESEncrypter(SecretKey key) {
    // Create an 8-byte initialization vector
    byte[] iv = new byte[] { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
            0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f };

    AlgorithmParameterSpec paramSpec = new IvParameterSpec(iv);
    try {
        ecipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        dcipher = Cipher.getInstance("AES/CBC/PKCS5Padding");

        // CBC requires an initialization vector
        ecipher.init(Cipher.ENCRYPT_MODE, key, paramSpec);
        dcipher.init(Cipher.DECRYPT_MODE, key, paramSpec);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

解密后，我得到一个无效的密钥异常：java.security.InvalidKeyException：无效的AES密钥长度：64字节。为什么会这样？有解决方案吗？

Answer 1

您的密钥生成功能存在缺陷 - 它只生成整数并将其转换为字符串，大大减少了可用的密钥空间并显着削弱了密钥。

但是，它确实产生了适合AES密钥的16字节值。我只能假设您上次收到错误消息后已更改了代码？

我强烈建议您恢复使用KeyGenerator来生成AES密钥。这将以安全的方式实现。

Java - SHA-256散列：无效的AES密钥长度：64字节

1 个答案: