Linux进行AES加密每次结果都不一致并且解密失败报错

Posted 2022-12-04 黄小斜

1. 现象

windows操作系统下进行"123456"的AES加密

encrypted message is below :

QLNYZyjRnKF/zxAjzDt/lw==

decrypted message is below :

123456

阿里云服务器，同样是"123456"的密码，每次加密结果都不一样，且不是QLNYZyjRnKF/zxAjzDt/lw==，解密是报错的

2.解决方法

经过检查之后，定位在生成KEY的方法上，如下：

public static Key getSecretKey(String key) throws Exception 
    SecretKey secureKey = null;
    if (key == null) 
        key = "";
    
    KeyGenerator keyGenerator = KeyGenerator.getInstance("AES");
    keyGenerator.init(new SecureRandom(key.getBytes()));
    secureKey = keyGenerator.generateKey();
    return secureKey;

修改到如下方式，问题解决：

public static Key getKey(String strKey) 
    try 
        if (strKey == null) 
            strKey = "";
        
        KeyGenerator _generator = KeyGenerator.getInstance("AES");
        SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG");
        secureRandom.setSeed(strKey.getBytes());
        _generator.init(128, secureRandom);
        return _generator.generateKey();
     catch (Exception e) 
        throw new RuntimeException(" 初始化密钥出现异常 ");
    

3.原因分析

原因一：

SecureRandom 实现完全隨操作系统本身的内部状态，除非调用方在调用 getInstance 方法之后又调用了 setSeed 方法；该实现在 windows 上每次生成的 key 都相同，但是在 solaris 或部分 linux 系统上则不同。

原因二：

1、加密完byte[] 后，需要将加密了的byte[] 转换成base64保存，如： 
BASE64Encoder base64encoder = new BASE64Encoder(); 
String encode=base64encoder.encode(bytes)； 

2、解密前，需要将加密后的字符串从base64转回来再解密，如： 
BASE64Decoder base64decoder = new BASE64Decoder(); 
byte[] encodeByte = base64decoder.decodeBuffer(str); 

4. 附录完整代码

package com.binfoo.wechat.util;

import java.security.Key;
import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

public class SecurityUtil 
    public static String DES = "AES"; // optional value AES/DES/DESede

    public static String CIPHER_ALGORITHM = "AES"; // optional value AES/DES/DESede


    public static Key getKey(String strKey) 
        try 
            if (strKey == null) 
                strKey = "";
            
            KeyGenerator _generator = KeyGenerator.getInstance("AES");
            SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG");
            secureRandom.setSeed(strKey.getBytes());
            _generator.init(128, secureRandom);
            return _generator.generateKey();
         catch (Exception e) 
            throw new RuntimeException(" 初始化密钥出现异常 ");
        
    

    public static String encrypt(String data, String key) throws Exception 
        SecureRandom sr = new SecureRandom();
        Key secureKey = getKey(key);
        Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, secureKey, sr);
        byte[] bt = cipher.doFinal(data.getBytes());
        String strS = new BASE64Encoder().encode(bt);
        return strS;
    


    public static String decrypt(String message, String key) throws Exception 
        SecureRandom sr = new SecureRandom();
        Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
        Key secureKey = getKey(key);
        cipher.init(Cipher.DECRYPT_MODE, secureKey, sr);
        byte[] res = new BASE64Decoder().decodeBuffer(message);
        res = cipher.doFinal(res);
        return new String(res);
    

    public static void main(String[] args) throws Exception 
        String message = "123456";
        String key = "landLeaf";
        String encryptMsg = encrypt(message, key);
        System.out.println("encrypted message is below :");
        System.out.println(encryptMsg);

        String decryptedMsg = decrypt(encryptMsg, key);
        System.out.println("decrypted message is below :");
        System.out.println(decryptedMsg);