Android的AES加密盘块损坏 [英] Android aes encryption pad block corrupted

问题描述

我使用的方法如下，如果我进入右键一切工作正常。 但是，如果我输入了错误的键，我收到一个BadPaddingException：垫块损坏... 难道我做错了什么？

 公共无效initKey（字符串passwd文件，byte []的盐）抛出抛出：NoSuchAlgorithmException，InvalidKeySpecException，NoSuchProviderException {

    byte []的localsalt =盐;
   PBEKeySpec密码=新PBEKeySpec（passwd.toCharArray（），localsalt，1024,128）; //，localsalt，1000，128）; // 128bit的AES ENC
   SecretKeyFactory工厂= SecretKeyFactory.getInstance（PBEWithMD5And128BitAES-CBC-OpenSSL的，BC）;
   PBEKey调用键=（PBEKey调用）factory.generateSecret（密码）;
   encKey =新SecretKeySpec（key.getEn codeD（），AES）;
}


公共字符串txt2enc（字符串etxt）抛出抛出：NoSuchAlgorithmException，NoSuchPaddingException，InvalidKeyException将，IllegalBlockSizeException，BadPaddingException，UnsupportedEncodingException {

       最后密码加密= Cipher.getInstance（AES）; // AES
       cipher.init（Cipher.ENCRYPT_MODE，encKey）;

       byte []的加密= cipher.doFinal（（etxt）.getBytes（UTF-8））;
       返回Base64.en codeToString（加密，0）;
}

//解密
公共字符串txt2dec（字符串dtxt）抛出InvalidKeyException将，抛出：NoSuchAlgorithmException，NoSuchPaddingException，IllegalBlockSizeException，BadPaddingException，UnsupportedEncodingException {

    最后密码加密= Cipher.getInstance（AES）;
    cipher.init（Cipher.DECRYPT_MODE，encKey）;
    byte []的解密= cipher.doFinal（Base64.de code（dtxt，0））;
    返回新的String（解密）; //返回Base64.en codeToString（解密，0）;
}
 

解决方案

你没有做错什么。它的预期。这在技术上是的Java加密问题（这似乎并不很容易找到）的副本。看到这个回答一个很好的解释。可以考虑增加一个MAC（消息认证code）安全地完成更多的东西像一个校验和。

I am using the methods below and if I enter the right key everything works fine. But if I enter a wrong key I am receiving a BadPaddingException:pad block corrupted... Am I doing something wrong?

public  void initKey(String passwd, byte[] salt) throws NoSuchAlgorithmException, InvalidKeySpecException, NoSuchProviderException{

    byte[] localsalt = salt; 
   PBEKeySpec password = new PBEKeySpec(passwd.toCharArray(),localsalt, 1024,128);//, localsalt, 1000, 128);  //128bit enc aes
   SecretKeyFactory factory = SecretKeyFactory.getInstance("PBEWithMD5And128BitAES-CBC-OpenSSL","BC");  
   PBEKey key = (PBEKey) factory.generateSecret(password);  
   encKey = new SecretKeySpec(key.getEncoded(), "AES");
}


public   String txt2enc(String etxt) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException, UnsupportedEncodingException {

       final Cipher cipher = Cipher.getInstance("AES");//AES       
       cipher.init(Cipher.ENCRYPT_MODE, encKey);      

       byte[] encrypted = cipher.doFinal((etxt).getBytes("UTF-8"));
       return Base64.encodeToString(encrypted, 0);
}

//decryption
public  String txt2dec(String dtxt) throws InvalidKeyException, NoSuchAlgorithmException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException, UnsupportedEncodingException{

    final Cipher cipher = Cipher.getInstance("AES");
    cipher.init(Cipher.DECRYPT_MODE, encKey);
    byte[] decrypt = cipher.doFinal(Base64.decode(dtxt, 0));
    return new String(decrypt);//return Base64.encodeToString(decrypt, 0);
}

解决方案

You're not doing anything wrong. It's expected. This is technically a duplicate of Java Encryption issue (which doesn't seem to be easy to find). See this answer for a good explanation. You can consider adding a MAC (Message Authentication Code) to safely accomplish something more like a checksum.

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