des 加密解密

package com.channelsoft.cellphone.background.login.util; 


import java.security.*; 


import javax.crypto.KeyGenerator; 

import javax.crypto.Cipher; 


/** 

 * 使用DES加密與解密,可對byte[],String類型進行加密與解密 密文可使用String,byte[]存儲 

 * @author lenovo 

 * 

 */ 

public class DesUtil { 

 private static Key key; 


 public static void getKey(String strKey) { 

 try { 

 KeyGenerator _generator = KeyGenerator.getInstance("DES"); 

 _generator.init(new SecureRandom(strKey.getBytes())); 

 key = _generator.generateKey(); 

 _generator = null; 

 } catch (Exception e) { 

 e.printStackTrace(); 

 } 

 } 

 //加密String明文輸入,String密文輸出 

 public static 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 null; 

 } 


 //解密 以String密文輸入,String明文輸出 

 public static 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[]明文輸入,byte[]密文輸出 

 private static 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[]密文輸入,以byte[]明文輸出 

 private static 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; 

 } 


 //二行制轉字元串 

 public static String byte2hex(byte[] b) { // 一個位元組的數， 

 // 轉成16進制字元串 

 String hs = ""; 

 String stmp = ""; 

 for (int n = 0; n < b.length; n++) { 

 // 整數轉成十六進制表示 

 stmp = (java.lang.Integer.toHexString(b[n] & 0XFF)); 

 if (stmp.length() == 1) 

 hs = hs + "0" + stmp; 

 else 

 hs = hs + stmp; 

 } 

 return hs.toUpperCase(); // 轉成大寫 

 } 


 public static byte[] hex2byte(byte[] b) { 

 if ((b.length % 2) != 0) 

 throw new IllegalArgumentException("長度不是偶數"); 

 byte[] b2 = new byte[b.length / 2]; 

 for (int n = 0; n < b.length; n += 2) { 

 String item = new String(b, n, 2); 

 // 兩位一組，表示一個位元組,把這樣表示的16進制字元串，還原成一個進制位元組 

 b2[n / 2] = (byte) Integer.parseInt(item, 16); 

 } 

 return b2; 

 } 



 /** 

 * DES加密解密算法 

 * @param args 

 * @CreateDate:2012-8-7 

 * @author yangliulv 

 */ 

 public static void main(String[] args) { 

 // TODO Auto-generated method stub 

// DesUtil des = new DesUtil(); //執行個體化一個對像 

// des.getKey("aadd"); //生成密匙 

// 

// String strEnc = des.getEncString("明文122"); //加密字元串,傳回String的密文 

// System.out.println(strEnc+":加密後長度為"+strEnc.length()); 

// 

// //解密 

// String strDes = des.getDesString(strEnc); //把String 類型的密文解密 

// System.out.println(strDes); 

 String key = ResourceConfig.getDesKey(); 

 DesUtil.getKey(key); //生成密匙 


 String strEnc = DesUtil.getEncString("明文122"); //加密字元串,傳回String的密文 

 System.out.println(strEnc+":加密後長度為"+strEnc.length()); 


 //解密 

 String strDes = DesUtil.getDesString(strEnc); //把String 類型的密文解密 

 System.out.println(strDes); 

 } 


}