解决Linux操作系统下AES解密失败的问题

现象描述：

windows上加解密正常，linux上加密正常，解密时发生如下异常：

javax.crypto.BadPaddingException: Given final block not properly padded

       at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
       at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
       at com.sun.crypto.provider.AESCipher.engineDoFinal(DashoA13*..)
       at javax.crypto.Cipher.doFinal(DashoA13*..)
       at chb.test.crypto.AESUtils.crypt(AESUtils.java:386)
       at chb.test.crypto.AESUtils.AesDecrypt(AESUtils.java:254)
       at chb.test.crypto.AESUtils.main(AESUtils.java:40) 

解决方法：

经过检查之后，定位在生成KEY的方法上，如下：

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

修改到如下方式，问题解决：

public static SecretKey getKey(String strKey) {
       try {
          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 " );
      }
    }

原因分析

SecureRandom 实现完全隨操作系统本身的內部狀態，除非調用方在調用 getInstance 方法之後又調用了 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); 

完整例子：

package com.travelsky.tdp.pkgStock.util;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

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

public class SecurityAES {
	private final static String encoding = "UTF-8"; 
	/**
	 * AES加密
	 * 
	 * @param content
	 * @param password
	 * @return
	 */
	public static String encryptAES(String content, String password) {
		byte[] encryptResult = encrypt(content, password);
		String encryptResultStr = parseByte2HexStr(encryptResult);
		// BASE64位加密
		encryptResultStr = ebotongEncrypto(encryptResultStr);
		return encryptResultStr;
	}

	/**
	 * AES解密
	 * 
	 * @param encryptResultStr
	 * @param password
	 * @return
	 */
	public static String decrypt(String encryptResultStr, String password) {
		// BASE64位解密
		String decrpt = ebotongDecrypto(encryptResultStr);
		byte[] decryptFrom = parseHexStr2Byte(decrpt);
		byte[] decryptResult = decrypt(decryptFrom, password);
		return new String(decryptResult);
	}

		/**
	 * 加密字符串
	 */
	public static String ebotongEncrypto(String str) {
		BASE64Encoder base64encoder = new BASE64Encoder();
		String result = str;
		if (str != null && str.length() > 0) {
			try {
				byte[] encodeByte = str.getBytes(encoding);
				result = base64encoder.encode(encodeByte);
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
		//base64加密超过一定长度会自动换行 需要去除换行符
		return result.replaceAll("\r\n", "").replaceAll("\r", "").replaceAll("\n", "");
	}

	/**
	 * 解密字符串
	 */
	public static String ebotongDecrypto(String str) {
		BASE64Decoder base64decoder = new BASE64Decoder();
		try {
			byte[] encodeByte = base64decoder.decodeBuffer(str);
			return new String(encodeByte);
		} catch (IOException e) {
			e.printStackTrace();
			return str;
		}
	}
	/**  
	 * 加密  
	 *   
	 * @param content 需要加密的内容  
	 * @param password  加密密码  
	 * @return  
	 */  
	private static byte[] encrypt(String content, String password) {   
	        try {              
	                KeyGenerator kgen = KeyGenerator.getInstance("AES"); 
	                //防止linux下 随机生成key
	                SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG" );   
	                secureRandom.setSeed(password.getBytes());   
	                kgen.init(128, secureRandom);
	                //kgen.init(128, new SecureRandom(password.getBytes()));   
	                SecretKey secretKey = kgen.generateKey();   
	                byte[] enCodeFormat = secretKey.getEncoded();   
	                SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");   
	                Cipher cipher = Cipher.getInstance("AES");// 创建密码器   
	                byte[] byteContent = content.getBytes("utf-8");   
	                cipher.init(Cipher.ENCRYPT_MODE, key);// 初始化   
	                byte[] result = cipher.doFinal(byteContent);   
	                return result; // 加密   
	        } catch (NoSuchAlgorithmException e) {   
	                e.printStackTrace();   
	        } catch (NoSuchPaddingException e) {   
	                e.printStackTrace();   
	        } catch (InvalidKeyException e) {   
	                e.printStackTrace();   
	        } catch (UnsupportedEncodingException e) {   
	                e.printStackTrace();   
	        } catch (IllegalBlockSizeException e) {   
	                e.printStackTrace();   
	        } catch (BadPaddingException e) {   
	                e.printStackTrace();   
	        }   
	        return null;   
	}  


	/**解密  
	 * @param content  待解密内容  
	 * @param password 解密密钥  
	 * @return  
	 */  
	private static byte[] decrypt(byte[] content, String password) {   
	        try {   
	                 KeyGenerator kgen = KeyGenerator.getInstance("AES"); 
	               //防止linux下 随机生成key
		             SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG" );   
		             secureRandom.setSeed(password.getBytes());   
		             kgen.init(128, secureRandom);
	                 //kgen.init(128, new SecureRandom(password.getBytes()));   
	                 SecretKey secretKey = kgen.generateKey();   
	                 byte[] enCodeFormat = secretKey.getEncoded();   
	                 SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");               
	                 Cipher cipher = Cipher.getInstance("AES");// 创建密码器   
	                cipher.init(Cipher.DECRYPT_MODE, key);// 初始化   
	                byte[] result = cipher.doFinal(content);   
	                return result; // 加密   
	        } catch (NoSuchAlgorithmException e) {   
	                e.printStackTrace();   
	        } catch (NoSuchPaddingException e) {   
	                e.printStackTrace();   
	        } catch (InvalidKeyException e) {   
	                e.printStackTrace();   
	        } catch (IllegalBlockSizeException e) {   
	                e.printStackTrace();   
	        } catch (BadPaddingException e) {   
	                e.printStackTrace();   
	        }   
	        return null;   
	}  

	/**将二进制转换成16进制  
	 * @param buf  
	 * @return  
	 */  
	public static String parseByte2HexStr(byte buf[]) {   
	        StringBuffer sb = new StringBuffer();   
	        for (int i = 0; i < buf.length; i++) {   
	                String hex = Integer.toHexString(buf[i] & 0xFF);   
	                if (hex.length() == 1) {   
	                        hex = '0' + hex;   
	                }   
	                sb.append(hex.toUpperCase());   
	        }   
	        return sb.toString();   
	}  


	/**将16进制转换为二进制  
	 * @param hexStr  
	 * @return  
	 */  
	public static byte[] parseHexStr2Byte(String hexStr) {   
	        if (hexStr.length() < 1)   
	                return null;   
	        byte[] result = new byte[hexStr.length()/2];   
	        for (int i = 0;i< hexStr.length()/2; i++) {   
	                int high = Integer.parseInt(hexStr.substring(i*2, i*2+1), 16);   
	                int low = Integer.parseInt(hexStr.substring(i*2+1, i*2+2), 16);   
	                result[i] = (byte) (high * 16 + low);   
	        }   
	        return result;   
	}  


	
}