DES加密解密的详细例子

来源：互联网发布：mac apache php mysql 编辑：程序博客网时间：2024/06/13 12:52

本人想通过一个简单加密和解密来对通讯的字符串进行安全监控。经过一番的查找后，并对其进行了完整的整理。得出如下本人的代码，该代码经过了测试！

import   java.security.Key;
import   java.security.SecureRandom;
import   javax.crypto.Cipher;
import   javax.crypto.KeyGenerator;
import   sun.misc.BASE64Decoder;
import   sun.misc.BASE64Encoder;

/**
*
*   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
{
private static Key key;
/**
   *   根据参数生成KEY
   *   @param   strKey
   */
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明文输入,String密文输出
* @param strMing
* @param key
* @return
*/
public static String getEncString(String strMing,String key){
  byte[]   byteMi   =   null;
  byte[]   byteMing   =   null;
  String   strMi   =   "";
  BASE64Encoder   base64en   =   new   BASE64Encoder();
  try {
   getKey(key);
   byteMing   =   strMing.getBytes("GB2312");
   byteMi   =   getEncCode(byteMing);
   strMi   =   base64en.encode(byteMi);
  }catch(Exception   e){
   e.printStackTrace();
  }finally {
   base64en   =   null;
   byteMing   =   null;
   byteMi   =   null;
  }
  return   strMi;
}
/**
   *   解密   以String密文输入,String明文输出
   *   @param   strMi
   *   @return
   */
public static String getDesString(String strMi,String key){
  BASE64Decoder   base64De   =   new   BASE64Decoder();
  byte[]   byteMing   =   null;
  byte[]   byteMi   =   null;
  String   strMing   =   "";
  try{
   getKey(key);
   byteMi = base64De.decodeBuffer(strMi);
   byteMing = getDesCode(byteMi);
   strMing = new String(byteMing,"GB2312");
  }catch(Exception   e){
   e.printStackTrace();
  }finally{
   base64De   =   null;
   byteMing   =   null;
   byteMi   =   null;
  }
  return   strMing;
}
/**
   *   加密以byte[]明文输入,byte[]密文输出
   *   @param   byteS
   *   @return
   */
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[]密文输入,以byte[]明文输出
   *   @param   byteD
   *   @return
   */
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;
}
public static void main(String args[]){
   DesEncrypt des = new DesEncrypt();
   String   strEnc   =   des.getEncString("OKID","xxx");//加密字符串,返回String的密文
   System.out.println(strEnc);
   String   strDes   =   des.getDesString(strEnc,"xxx");//把String   类型的密文解密
   System.out.println(strDes);
}
}