实验五 Java网络编程及安全
实验内容
1．掌握Socket程序的编写；
2．掌握密码技术的使用；
3．设计安全
实验步骤
1.信息安全传送：
发送方A——————>接收方B
A加密时，用B的公钥
B解密时，用B的私钥
发送方A对信息(明文)采用DES密钥加密,使用RSA加密前面的DES密钥信息,最终将混合信息进行传递。接收方B接收到信息后，用RSA解密DES密钥信息，再用RSA解密获取到的密钥信息解密密文信息，最终就可以得到我们要的信息(明文)。
实验代码
服务器：
// file name：ComputeTCPServer.java
import java.net.*;import java.io.*;import java.security.*;import java.security.spec.*;import javax.crypto.*;import javax.crypto.spec.*;import javax.crypto.interfaces.*;import java.security.interfaces.*;import java.math.*;public class ComputeTCPServer{ public static void main(String srgs[]) throws Exception { ServerSocket sc = null; Socket socket=null; try { sc= new ServerSocket(4421);//创建服务器套接字 System.out.println("端口号:" + sc.getLocalPort()); System.out.println("服务器已经启动..."); socket = sc.accept(); //等待客户端连接 System.out.println("已经建立连接"); //获得网络输入流对象的引用 BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream())); 获得网络输出流对象的引用 PrintWriter out=new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())),true); String aline2=in.readLine(); BigInteger c=new BigInteger(aline2); FileInputStream f=new FileInputStream("Skey_RSA_priv.dat"); ObjectInputStream b=new ObjectInputStream(f); RSAPrivateKey prk=(RSAPrivateKey)b.readObject( ); BigInteger d=prk.getPrivateExponent(); BigInteger n=prk.getModulus(); //System.out.println("d= "+d); //System.out.println("n= "+n); BigInteger m=c.modPow(d,n); //System.out.println("m= "+m); byte[] keykb=m.toByteArray(); //String aline3=new String(mt,"UTF8"); //String aline3=parseByte2HexStr(byte buf[]); String aline=in.readLine();//读取客户端传送来的数据 //FileInputStream f2=new FileInputStream("keykb1.dat"); //int num2=f2.available(); //byte[] keykb=new byte[num2]; //f2.read(keykb); byte[] ctext=parseHexStr2Byte(aline); Key k=new SecretKeySpec(keykb,"DESede"); Cipher cp=Cipher.getInstance("DESede"); cp.init(Cipher.DECRYPT_MODE, k); byte []ptext=cp.doFinal(ctext); String p=new String(ptext,"UTF8"); System.out.println("从客户端接收到信息为："+p); //通过网络输出流返回结果给客户端 /*String aline2=in.readLine(); BigInteger c=new BigInteger(aline2); FileInputStream f=new FileInputStream("Skey_RSA_priv.dat"); ObjectInputStream b=new ObjectInputStream(f); RSAPrivateKey prk=(RSAPrivateKey)b.readObject( ); BigInteger d=prk.getPrivateExponent(); BigInteger n=prk.getModulus(); //System.out.println("d= "+d); //System.out.println("n= "+n); BigInteger m=c.modPow(d,n); //System.out.println("m= "+m); byte[] mt=m.toByteArray(); //String aline3=new String(mt,"UTF8");*/ String aline3=in.readLine(); String x=p; MessageDigest m2=MessageDigest.getInstance("MD5"); m2.update(x.getBytes( )); byte a[ ]=m2.digest( ); String result=""; for (int i=0; i<a.length; i++){ result+=Integer.toHexString((0x000000ff & a[i]) | 0xffffff00).substring(6); } System.out.println(result); if(aline3.equals(result)){ System.out.println("匹配成功"); } out.println("匹配成功"); out.close(); in.close(); sc.close(); } catch (Exception e) { System.out.println(e); } } public static String parseByte2HexStr(byte buf[]) { StringBuffer sb = new StringBuffer(); for (int i = 0; i < buf.length; i++) { String hex = Integer.toHexString(buf[i] & 0xFF); if (hex.length() == 1) { hex = '0' + hex; } sb.append(hex.toUpperCase()); } return sb.toString(); } public static byte[] parseHexStr2Byte(String hexStr) { if (hexStr.length() < 1) return null; byte[] result = new byte[hexStr.length()/2]; for (int i = 0;i< hexStr.length()/2; i++) { int high = Integer.parseInt(hexStr.substring(i*2, i*2+1 ), 16); int low = Integer.parseInt(hexStr.substring(i*2+1, i*2+2), 16); result[i] = (byte) (high * 16 + low); } return result; } }
客户端：
// file name：ComputeTCPClient.java
import java.net.*;import java.io.*;import java.security.*;import javax.crypto.*;import javax.crypto.spec.*;import java.security.spec.*;import javax.crypto.interfaces.*;import java.security.interfaces.*;import java.math.*;public class ComputeTCPClient { public static void main(String srgs[]) throws Exception{ try { KeyGenerator kg=KeyGenerator.getInstance("DESede");//方法getInstance（ ）的参数为字符串类型，指定加密算法的名称 kg.init(168); //该步骤一般指定密钥的长度 SecretKey k=kg.generateKey( );//生成密钥 byte[] ptext2=k.getEncoded(); //String kstr=parseByte2HexStr(kb); //创建连接特定服务器的指定端口的Socket对象 //Socket socket = new Socket("192.168.155.4", 4421); Socket socket = new Socket("192.168.8.102", 4421); //获得从服务器端来的网络输入流 BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream())); //获得从客户端向服务器端输出数据的网络输出流 PrintWriter out=new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())),true); //创建键盘输入流，以便客户端从键盘上输入信息 BufferedReader stdin = new BufferedReader(new InputStreamReader(System.in)); FileInputStream f3=new FileInputStream("Skey_RSA_pub.dat"); ObjectInputStream b2=new ObjectInputStream(f3); RSAPublicKey pbk=(RSAPublicKey)b2.readObject( ); BigInteger e=pbk.getPublicExponent(); BigInteger n=pbk.getModulus(); //System.out.println("e= "+e); //System.out.println("n= "+n); //byte ptext2[]=kstr.getBytes("UTF8"); BigInteger m=new BigInteger(ptext2); BigInteger c=m.modPow(e,n); //System.out.println("c= "+c); String cs=c.toString( ); out.println(cs); //通过网络传送到服务器 System.out.print("请输入待发送的数据："); String s=stdin.readLine(); //从键盘读入待发送的数据 Cipher cp=Cipher.getInstance("DESede"); cp.init(Cipher.ENCRYPT_MODE, k); byte ptext[]=s.getBytes("UTF8"); byte ctext[]=cp.doFinal(ptext); String str=parseByte2HexStr(ctext); out.println(str); //通过网络传送到服务器 String x=s; MessageDigest m2=MessageDigest.getInstance("MD5"); m2.update(x.getBytes( )); byte a[ ]=m2.digest( ); String result=""; for (int i=0; i<a.length; i++){ result+=Integer.toHexString((0x000000ff & a[i]) | 0xffffff00).substring(6); } System.out.println(result); out.println(result); /*s=result; FileInputStream f3=new FileInputStream("Skey_RSA_pub.dat"); ObjectInputStream b2=new ObjectInputStream(f3); RSAPublicKey pbk=(RSAPublicKey)b2.readObject( ); BigInteger e=pbk.getPublicExponent(); BigInteger n=pbk.getModulus(); //System.out.println("e= "+e); //System.out.println("n= "+n); byte ptext2[]=s.getBytes("UTF8"); BigInteger m=new BigInteger(ptext2); BigInteger c=m.modPow(e,n); //System.out.println("c= "+c); String cs=c.toString( ); out.println(cs); //通过网络传送到服务器*/ str=in.readLine();//从网络输入流读取结果 System.out.println( "从服务器接收到的结果为："+str); //输出服务器返回的结果 } catch (Exception e) { System.out.println(e); } finally{ //stdin.close(); //in.close(); //out.close(); //socket.close(); } } public static String parseByte2HexStr(byte buf[]) { StringBuffer sb = new StringBuffer(); for (int i = 0; i < buf.length; i++) { String hex = Integer.toHexString(buf[i] & 0xFF); if (hex.length() == 1) { hex = '0' + hex; } sb.append(hex.toUpperCase()); } return sb.toString(); } public static byte[] parseHexStr2Byte(String hexStr) { if (hexStr.length() < 1) return null; byte[] result = new byte[hexStr.length()/2]; for (int i = 0;i< hexStr.length()/2; i++) { int high = Integer.parseInt(hexStr.substring(i*2, i*2+1), 16); int low = Integer.parseInt(hexStr.substring(i*2+1, i*2+2), 16); result[i] = (byte) (high * 16 + low); } return result; } }连接结果截图
实验总结：
本次实验觉得是有一定的难度的，在读老师给的代码时，看得不是很懂，其中还用到了有关密码学的知识，所以，通过询问别人，自己上网查询，最终完成了实验。