問題描述

我幾乎是加密新手.

我正在嘗試解密一個字節數組，當我提供 IV 時，我遇到了一個異常:InvalidAlgorithmParameterException(預期時未設置 iv).

I am trying to decrypt an array of bytes, and when I am providing the IV I am getting an exception : InvalidAlgorithmParameterException (no iv set when one expected).

這是我的代碼(iv 是一個 16 字節的數組，它不為空，并且具有加密時使用的值):

Here's my code (iv is an array of 16 bytes which is not null and has the values used when encrypting) :

Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE, encriptionKey,new IvParameterSpec(iv));

如果我沒有指定 IV，密碼會被初始化:

If I don't specify the IV the cipher gets initialized ok :

Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE, encriptionKey);

試圖找到答案，我確實找到了 JCEStreamCipher 的實現(here) 這可能與我使用的版本不對應，但有一些代碼讓我覺得我沒有正確理解它.

Trying to find an answer I did find an implementation of JCEStreamCipher (here) which may not correspond to the version I am using but has some code that makes me thing I am not understanding it correctly.

代碼如下:

   if ((ivLength != 0) && !(param instanceof ParametersWithIV))
    {
        SecureRandom    ivRandom = random;

        if (ivRandom == null)
        {
            ivRandom = new SecureRandom();
        }

        if ((opmode == Cipher.ENCRYPT_MODE) || (opmode == Cipher.WRAP_MODE))
        {
            byte[]  iv = new byte[ivLength];

            ivRandom.nextBytes(iv);
            param = new ParametersWithIV(param, iv);
            ivParam = (ParametersWithIV)param;
        }
        else
        {
            throw new InvalidAlgorithmParameterException("no IV set when one expected");
        }
    }

看起來我在解密時無法提供 IV，但這對我來說沒有太大意義.

Looks like I cannot provide an IV when decrypting, but it doesn't makes too much sense to me.

任何幫助將不勝感激.

非常感謝，理查德.

推薦答案

已解決.

我使用了錯誤的 SecretKey，而不是您可以為 AES 創建的密鑰.

I was using a wrong SecretKey, not the one you can create for AES.

以前我有:

KeySpec spec = new PBEKeySpec(password.toCharArray(), encryptionKeySalt, 12345,256);
SecretKey encriptionKey = factory.generateSecret(spec);

創建一個 JCEPBEKey.

which creates a JCEPBEKey.

我失蹤了:

Key encriptionKey = new SecretKeySpec(encriptionKey.getEncoded(), "AES"); 

為 AES 創建一個適當的密鑰.

which creates an appropiate key for AES.

這篇關于解密錯誤:“沒有預期的 iv 設置"的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！