AES加密【轉】

 

.

 

此時就一定要使用如下代碼步驟 :

1.SecureRandom的key定下來.

SecureRandom 實現完全隨操作系統本身的內部狀態，除非調用方在調用 getInstance 方法之後又調用了 setSeed 方法；

該實現在 windows 上每次生成的 key 都相同，但是在 solaris 或部分 linux 系統上則不同.

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( " 初始化密鑰出現異常 " );  
      }  
    }

 

2. 16進制轉換為2進制 互轉

* 因為加密后的byte數組是不能強制轉換成字符串的，
* 換言之：字符串和byte數組在這種情況下不是互逆的；
* 要避免這種情況，我們需要做一些修訂，可以考慮將二進制數據轉換成十六進制表示

 

3. BASE64加解密 

 這個原因和2有點類似,仿佛有點多余,也許能省下這一步.

 

 4. 如果不這么做

windows上加解密正常，linux上加密正常，解密時發生如下異常：

 

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) 

而我自己遇上的情況比這更糟,同樣的windows環境,

用apache的httppost發送加密報文在tomcat服務端進行解密就會報以上異常,

但是用java原生態的UrlConnection發送加密報文在tomcat服務端進行解密一切正常.

可能是apache對發送的流填充模式不同吧@@！

 

代碼示例

package com.testdemo.validate.endecrypt;
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 AESTool {  
    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 = encryptBASE64(encryptResultStr);  
        return encryptResultStr;  
    }  
  
    /** 
     * AES解密 
     *  
     * @param encryptResultStr 
     * @param password 
     * @return 
     */  
    public static String decryptAES(String encryptResultStr, String password) {  
        // BASE64位解密  
        String decrpt = decryptBASE64(encryptResultStr);  
        byte[] decryptFrom = parseHexStr2Byte(decrpt);  
        byte[] decryptResult = decrypt(decryptFrom, password);  
        return new String(decryptResult);  
    }  
  
        /** 
     * 加密字符串 
     */  
    public static String encryptBASE64(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加密超過一定長度會自動換行 需要去除換行符  
        return result.replaceAll("\r\n", "").replaceAll("\r", "").replaceAll("\n", "");  
    }  
  
    /** 
     * 解密字符串 
     */  
    public static String decryptBASE64(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 需要加密的內容   
     * @param password  加密密碼   
     * @return   
     */    
    private static byte[] encrypt(String content, String password) {     
            try {                
                    KeyGenerator kgen = KeyGenerator.getInstance("AES");   
                    //防止linux下 隨機生成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");// 創建密碼器     
                    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  待解密內容   
     * @param password 解密密鑰   
     * @return   
     */    
    private static byte[] decrypt(byte[] content, String password) {     
            try {     
                     KeyGenerator kgen = KeyGenerator.getInstance("AES");   
                   //防止linux下 隨機生成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");// 創建密碼器     
                    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;     
    }    
  
    /**將二進制轉換成16進制   
     * @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();     
    }    
  
  
    /**將16進制轉換為二進制   
     * @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;     
    }    
  
  
    public static void test1() {
        String content = "test";
        String password = "12345678";
        // 加密
        System.out.println("加密前：" + content);
        String encryptResult = encryptAES(content, password);
        System.out.println("加密后: "+ encryptResult);
        // 解密
        System.out.println("解密前: "+ encryptResult);
        String decryptResult = decryptAES(encryptResult, password);
        System.out.println("解密后：" + new String(decryptResult));
    }
    
    public static void main(String[] args) {
        test1();
    }
      
} 

 

http://konglx.iteye.com/blog/954085

http://www.cnblogs.com/freeliver54/archive/2011/10/08/2202136.html   java源碼下載