import java.rmi.*;
import java.rmi.server.*;
import java.io.*;
import java.security.*;

public class RMISignClient
  {
   public static void main(String[] args)
     {
      String RemoteSerHost = null;
      RMISignInterface rmisi = null;
      String outprint = null;
      RMISignObject rmiso = null;
      Signature signature = null;
      boolean isValid = false;
      String testTxt = null;

      try
        {
         RemoteSerHost = "//127.0.0.1/SignServer";
         testTxt = "It is a test";
         System.out.println("\n本地客戶機開始啟動...");
         rmisi = (RMISignInterface) Naming.lookup(RemoteSerHost);
         outprint = rmisi.putString(testTxt);    
         System.out.println("\n本地客戶機接收到的正文為: " + outprint);
         rmiso = rmisi.getSignObj();    //獲得RMI數字簽名對象
         System.out.println("RMI數字簽名對象為: " +rmiso.toString());
         signature = Signature.getInstance("SHA/DSA");
         signature.initVerify(rmiso.puk);
         signature.update(rmiso.seriTxt);       //更新數字簽名序列化的對象
         System.out.println("\nRMI數字簽名對象的公鑰為：" +rmiso.puk);
         isValid = signature.verify(rmiso.signTxt);     //判斷RMI數字簽名是否有效
         if(isValid == true)
           {
            System.out.println("這是有效的RMI數字簽名!");
           }
         else
           {
            System.out.println("這是無效的RMI數字簽名!");
           }
        }
      catch(Exception e)
        {
         System.out.println("! 客戶機在運行時拋出例外：" + e.toString());
        }
     }
  }