desencrypt.java

可以用来保持常用的帐号和密码的软件,保存常用的邮箱帐号密码以及网游

import   java.security.Key;   
import   java.security.SecureRandom;   
import   javax.crypto.Cipher;   
import   javax.crypto.KeyGenerator;  
import   java.io.*; 
  
    
/**   
    *     
    *   使用DES加密与解密,可对byte[],String类型进行加密与解密   
    *   密文可使用String,byte[]存储.   
    *     
    *   方法:   
    *   void   getKey(String   strKey)从strKey的字条生成一个Key   
    *     
    *   String   getEncString(String   strMing)对strMing进行加密,返回String密文   
    *   String   getDesString(String   strMi)对strMin进行解密,返回String明文   
    *     
    *byte[]   getEncCode(byte[]   byteS)byte[]型的加密   
    *byte[]   getDesCode(byte[]   byteD)byte[]型的解密   
*/   
    
public   class   DesEncrypt {   
   Key   key;   
    /**   
    *   根据参数生成KEY   
    *   @param   strKey   
    */   
    public   void   getKey(String   strKey) {   
        try{   
            KeyGenerator   _generator   =   KeyGenerator.getInstance("DES");   
            _generator.init(new   SecureRandom(strKey.getBytes()));   
            this.key   =   _generator.generateKey();   
            _generator=null;   
        }catch(Exception   e){   
            e.printStackTrace();   
        }   
    }   
    /**   
    *   加密String明文输入,String密文输出   
    *   @param   strMing   
    *   @return   
    */   
    public   String   getEncString(String   strMing) {   
        byte[]   byteMi   =   null;   
        byte[]   byteMing   =   null;   
        String   strMi   =   "";    
        try {    
            return byte2hex(getEncCode (strMing.getBytes() ) );

//            byteMing   =   strMing.getBytes("UTF8");   
//            byteMi   =   this.getEncCode(byteMing);   
//            strMi   =  new String( byteMi,"UTF8");
        }   
        catch(Exception   e){   
            e.printStackTrace();   
        }   
        finally {   
            byteMing   =   null;   
            byteMi   =   null;   
        }   
        return   strMi;   
    }   
    /**   
    *   解密   以String密文输入,String明文输出   
    *   @param   strMi   
    *   @return   
    */   
    public   String   getDesString(String   strMi)  {   
        byte[]   byteMing   =   null;   
        byte[]   byteMi   =   null;   
        String   strMing   =   "";   
        try  {   
            return new String(getDesCode(hex2byte(strMi.getBytes()) ));   

//            byteMing   =   this.getDesCode(byteMi);   
//            strMing   =   new   String(byteMing,"UTF8");   
        }   
        catch(Exception   e) {   
            e.printStackTrace();   
        }   
        finally {   
            byteMing   =   null;   
            byteMi   =   null;   
        }   
        return   strMing;   
    }   
    /**   
    *   加密以byte[]明文输入,byte[]密文输出   
    *   @param   byteS   
    *   @return   
    */   
    private   byte[]   getEncCode(byte[]   byteS) {   
        byte[]   byteFina   =   null;   
        Cipher   cipher;   
        try {   
            cipher   =   Cipher.getInstance("DES");   
            cipher.init(Cipher.ENCRYPT_MODE,   key);   
            byteFina   =   cipher.doFinal(byteS);   
        }   
        catch(Exception   e) {   
            e.printStackTrace();   
        }   
        finally {   
            cipher   =   null;   
        }   
        return   byteFina;   
    }   
    /**   
    *   解密以byte[]密文输入,以byte[]明文输出   
    *   @param   byteD   
    *   @return   
    */   
    private   byte[]   getDesCode(byte[]   byteD) {   
        Cipher   cipher;   
        byte[]   byteFina=null;   
        try{   
            cipher   =   Cipher.getInstance("DES");   
            cipher.init(Cipher.DECRYPT_MODE,   key);   
            byteFina   =   cipher.doFinal(byteD);   
        }catch(Exception   e){   
            e.printStackTrace();   
        }finally{   
            cipher=null;   
        }   
        return   byteFina;   
    }  
/**  
* 二行制转字符串  
* @param b  
* @return  
*/   
    public static String byte2hex(byte[] b) {   //一个字节的数，
        // 转成16进制字符串
       String hs = "";   
       String stmp = "";   
       for (int n = 0; n < b.length; n++) {   
           //整数转成十六进制表示
           stmp = (java.lang.Integer.toHexString(b[n] & 0XFF));  
           if (stmp.length() == 1)   
               hs = hs + "0" + stmp;   
           else   
               hs = hs + stmp;   
       }   
       return hs.toUpperCase();   //转成大写
  }   
    
   public static byte[] hex2byte(byte[] b) {   
      if((b.length%2)!=0)  
         throw new IllegalArgumentException("长度不是偶数");   
       byte[] b2 = new byte[b.length/2];   
       for (int n = 0; n < b.length; n+=2) {   
         String item = new String(b,n,2);   
         // 两位一组，表示一个字节,把这样表示的16进制字符串，还原成一个进制字节
         b2[n/2] = (byte)Integer.parseInt(item,16);   
       }   
   
       return b2;   
 }   


	/*    public   static   void   main(String[]   args)throws IOException{   

        DesEncrypt   des=new   DesEncrypt();//实例化一个对像   
         des.getKey("aadd");//生成密匙   
       
		BufferedReader din = new BufferedReader(new InputStreamReader(System.in));
		String inString = din.readLine();
        String   strEnc   =   des.getEncString(inString);//加密字符串,返回String的密文   
        System.out.println(strEnc);   

        String   strDes   =   des.getDesString(strEnc);//把String   类型的密文解密   
        System.out.println(strDes);   
      
    }  */ 

}