iu.java

它能够进行简单的文字聊天和基本的信息交换。

/*
 * client.java
 *
 
 *
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 * and open the template in the editor.
 */

/**
 *
 * @author codewar1
 */
import java.net.*;
import java.io.*;
import java.security.Security;
import java.security.*;
import javax.crypto.*;
import com.sun.crypto.provider.SunJCE;
public class iu{
    
  
    public static String key = "nuptcodewar";
   
    /** Creates a new instance of client */
    public iu() {
       
     }
      public static String encrypt(String message)
   {
       
      if (key.length()>message.length())
        {
            
             
            String longs = key+message;
            return longs;
            
             
        }
        else  
        {
            //String shorts = message.replace("a","d");
          String shorts = message+key;
            return shorts;
          //eturn message;
        }
        // return message;
        
         
   }
   
   public static String decrypt(String message)
   {
        int k = message.length();
        if (k<2*key.length())
        {
             
            String longs= message.substring(key.length());
            return longs;
        }
        else
        {
             
         //tring shorts = message.replace("d","a");
          int p = message.indexOf(key);
          String shorts= message.substring(0,p);
         return shorts;
            //eturn message;
          
        }
        //return message;
      
   }
    }