实验五实验报告
一、实验报告封面
课程：Java程序设计 班级：1752班 姓名：罗乐琦 学号：20175219
指导教师：娄嘉鹏 实验日期：2019年5月28日
实验时间：--- 实验序号：实验五
实验名称：网络编程与安全
二、实验内容与步骤
任务一要求
- 参考http://www.cnblogs.com/rocedu/p/6766748.html#SECDSA
- 结对实现中缀表达式转后缀表达式的功能 MyBC.java
- 结对实现从上面功能中获取的表达式中实现后缀表达式求值的功能,调用MyDC.java
- 上传测试代码运行结果截图和码云链接
实验代码
getHostAddress.java
import java.net.*;
public class getHostAddress {
public static void main(String[] args) {
try{
InetAddress hostaddress = InetAddress.getLocalHost();
System.out.println(hostaddress.toString());
}catch (UnknownHostException e){
System.out.println(e);
}
}
}
MyBC.java
import java.io.*;
import java.util.Stack;
public class MyBC {
public static void main(String[] args) {
int i, f;
double result;
int zuokuohao1 = 0;
String ch2 = new String();
BufferedReader buf = new BufferedReader(new InputStreamReader(System.in));
try {
String str = buf.readLine();
f = chu0.chu0(str);
if (f == 0) {
char[] ch1 = str.toCharArray();
int len1 = ch1.length;
Stack<Character> operators = new Stack<>();
Stack output = new Stack<>();
zuokuohao1 = rpn(operators, output, str);
for (i = 0; i < len1 - 2 * zuokuohao1; i++) {
ch2 = output.pop() + ch2;
}
System.out.println(ch2);
} else {
System.out.println("除数为0");
}
} catch (IOException e) {
}
}
public static int rpn(Stack<Character> operators, Stack output, String str) {
char[] chars = str.toCharArray();
int pre = 0;
boolean digital;
int zuokuohao = 0;
int len = chars.length;
int bracket = 0;
for (int i = 0; i < len; ) {
pre = i;
digital = Boolean.FALSE;
while (i < len && !Operator.isOperator(chars[i])) {
i++;
digital = Boolean.TRUE;
}
if (digital) {
output.push(str.substring(pre, i));
} else {
char o = chars[i++];
if (o == '(') {
bracket++;
zuokuohao++;
}
if (bracket > 0) {
if (o == ')') {
while (!operators.empty()) {
char top = operators.pop();
if (top == '(') {
break;
}
output.push(top);
}
bracket--;
} else {
while (!operators.empty() && operators.peek() != '(' && Operator.cmp(o, operators.peek()) <= 0) {
output.push(operators.pop());
}
operators.push(o);
}
} else {
while (!operators.empty() && Operator.cmp(o, operators.peek()) <= 0) {
output.push(operators.pop());
}
operators.push(o);
}
}
}
while (!operators.empty()) {
output.push(operators.pop());
}
return zuokuohao;
}
}
enum Operator {
ADD('+', 1), SUBTRACT('-', 1),
MULTIPLY('*', 2), DIVIDE('/', 2),
LEFT_BRACKET('(', 3), RIGHT_BRACKET(')', 3);
char value;
int priority;
Operator(char value, int priority) {
this.value = value;
this.priority = priority;
}
public static int cmp(char c1, char c2) {
int p1 = 0;
int p2 = 0;
for (Operator o : Operator.values()) {
if (o.value == c1) {
p1 = o.priority;
}
if (o.value == c2) {
p2 = o.priority;
}
}
return p1 - p2;
}
public static boolean isOperator(char c) {
for (Operator o : Operator.values()) {
if (o.value == c) {
return true;
}
}
return false;
}
}
class chu0 {
public static int chu0(String s) {
int i;
int flag = 0;
char[] ch = s.toCharArray();
for (i = 0; i < ch.length; i++) {
if (ch[i] == '/' && ch[i + 1] == '0') {
flag = 1;
}
}
return flag;
}
}
MyDC.java
import java.util.StringTokenizer;
import java.util.Stack;
public class MyDC {
/**
* constant for addition symbol
*/
private final char ADD = '+';
/**
* constant for subtraction symbol
*/
private final char SUBTRACT = '-';
/**
* constant for multiplication symbol
*/
private final char MULTIPLY = '*';
/**
* constant for division symbol
*/
private final char DIVIDE = '/';
/**
* the stack
*/
private Stack<Integer> stack;
public MyDC() {
stack = new Stack<Integer>();
}
public int evaluate(String expr) {
int op1, op2, result = 0;
String token;
StringTokenizer tokenizer = new StringTokenizer(expr);
while (tokenizer.hasMoreTokens()) {
token = tokenizer.nextToken();
//如果是运算符，调用isOperator
if (isOperator(token)) {
//从栈中弹出操作数2
op2 = stack.pop();
//从栈中弹出操作数1
op1 = stack.pop();
//根据运算符和两个操作数调用evalSingleOp计算result;
result = evalSingleOp(token.charAt(0), op1, op2);
//计算result入栈;
stack.push(result);
} else//如果是操作数
//操作数入栈;
stack.push(Integer.parseInt(token));
}
return result;
}
private boolean isOperator(String token) {
return (token.equals("+") || token.equals("-") ||
token.equals("*") || token.equals("/"));
}
private int evalSingleOp(char operation, int op1, int op2) {
int result = 0;
switch (operation) {
case ADD:
result = op1 + op2;
break;
case SUBTRACT:
result = op1 - op2;
break;
case MULTIPLY:
result = op1 * op2;
break;
case DIVIDE:
result = op1 / op2;
}
return result;
}
}
MyDCTester.java
import java.util.Scanner;
public class MyDCTester {
public static void main(String[] args) {
String expression, again;
int result;
try {
Scanner in = new Scanner(System.in);
do {
MyDC evaluator = new MyDC();
System.out.println("Enter a valid postfix expression: ");
expression = in.nextLine();
result = evaluator.evaluate(expression);
System.out.println();
System.out.println("That expression equals " + result);
System.out.print("Evaluate another expression [Y/N]? ");
again = in.nextLine();
System.out.println();
}
while (again.equalsIgnoreCase("y"));
} catch (Exception IOException) {
System.out.println("Input exception reported");
}
}
}
实验截图
任务二要求
- 1人负责客户端，1人负责服务器。
- 注意责任归宿，要会通过测试证明自己没有问题
- 基于Java Socket实现客户端/服务器功能，传输方式用TCP
- 客户端让用户输入中缀表达式，然后把中缀表达式调用MyBC.java的功能转化为后缀表达式，把后缀表达式通过网络发送给服务器
- 服务器接收到后缀表达式，调用MyDC.java的功能计算后缀表达式的值，把结果发送给客户端
- 客户端显示服务器发送过来的结果
- 上传测试结果截图和码云链接
实验代码
对MyBC.java稍做修改
import java.io.*;
import java.util.Stack;
public class MyBC {
public static String transform(String str) {
int i, f;
double result;
int zuokuohao1 = 0;
String ch2 = new String();
BufferedReader buf = new BufferedReader(new InputStreamReader(System.in));
f = chu0.chu0(str);
if (f == 0) {
char[] ch1 = str.toCharArray();
int len1 = ch1.length;
Stack<Character> operators = new Stack<>();
Stack output = new Stack<>();
zuokuohao1 = rpn(operators, output, str);
for (i = 0; i < len1 - 2 * zuokuohao1; i++) {
ch2 = output.pop() +" "+ ch2;
}
System.out.println("转换成后缀表达式："+ ch2);
} else {
System.out.println("除数为0");
}
return ch2;
}
public static int rpn(Stack<Character> operators, Stack output, String str) {
char[] chars = str.toCharArray();
int pre = 0;
boolean digital;
int zuokuohao = 0;
int len = chars.length;
int bracket = 0;
for (int i = 0; i < len; ) {
pre = i;
digital = Boolean.FALSE;
while (i < len && !Operator.isOperator(chars[i])) {
i++;
digital = Boolean.TRUE;
}
if (digital) {
output.push(str.substring(pre, i));
} else {
char o = chars[i++];
if (o == '(') {
bracket++;
zuokuohao++;
}
if (bracket > 0) {
if (o == ')') {
while (!operators.empty()) {
char top = operators.pop();
if (top == '(') {
break;
}
output.push(top);
}
bracket--;
} else {
while (!operators.empty() && operators.peek() != '(' && Operator.cmp(o, operators.peek()) <= 0) {
output.push(operators.pop());
}
operators.push(o);
}
} else {
while (!operators.empty() && Operator.cmp(o, operators.peek()) <= 0) {
output.push(operators.pop());
}
operators.push(o);
}
}
}
while (!operators.empty()) {
output.push(operators.pop());
}
return zuokuohao;
}
}
enum Operator {
ADD('+', 1), SUBTRACT('-', 1),
MULTIPLY('*', 2), DIVIDE('/', 2),
LEFT_BRACKET('(', 3), RIGHT_BRACKET(')', 3);
char value;
int priority;
Operator(char value, int priority) {
this.value = value;
this.priority = priority;
}
public static int cmp(char c1, char c2) {
int p1 = 0;
int p2 = 0;
for (Operator o : Operator.values()) {
if (o.value == c1) {
p1 = o.priority;
}
if (o.value == c2) {
p2 = o.priority;
}
}
return p1 - p2;
}
public static boolean isOperator(char c) {
for (Operator o : Operator.values()) {
if (o.value == c) {
return true;
}
}
return false;
}
}
class chu0 {
public static int chu0(String s) {
int i;
int flag = 0;
char[] ch = s.toCharArray();
for (i = 0; i < ch.length; i++) {
if (ch[i] == '/' && ch[i + 1] == '0') {
flag = 1;
}
}
return flag;
}
}
Sever2.java
import java.io.*;
import java.net.*;
public class Sever2 {
public static void main(String[] args) {
ServerSocket serverForClient = null;
Socket socketOnServer = null;
DataOutputStream out = null;
DataInputStream in = null;
MyDC myDC = new MyDC();
try{
serverForClient = new ServerSocket(2010);
}catch (IOException e){
System.out.println("端口已被占用"+e);
}
try{
System.out.println("等待客户呼叫");
socketOnServer = serverForClient.accept();
out = new DataOutputStream(socketOnServer.getOutputStream());
in = new DataInputStream(socketOnServer.getInputStream());
String suffix = in.readUTF();
System.out.println("收到后缀表达式："+suffix);
out.writeUTF(myDC.evaluate(suffix)+"");
Thread.sleep(500);
}catch (Exception e){
System.out.println("客户已断开"+e);
}
}
}
Client2.java
import java.io.*;
import java.net.*;
import java.util.Scanner;
import java.util.Stack;
public class Client2 {
public static void main(String[] args) {
Scanner inn = new Scanner(System.in);
Socket mysocket;
DataInputStream in = null;
DataOutputStream out = null;
try{
mysocket = new Socket("192.168.56.1",2010);
in = new DataInputStream(mysocket.getInputStream());
out = new DataOutputStream(mysocket.getOutputStream());
System.out.println("请输入运算式：");
String str = inn.nextLine();
String suffix = MyBC.transform(str);
out.writeUTF(suffix);
String result = in.readUTF();
System.out.println("求值为："+result);
Thread.sleep(500);
}catch (Exception e){
System.out.println("服务器已断开"+e)#;
}
}
}
实验截图
任务三要求
- 1人负责客户端，1人负责服务器
- 注意责任归宿，要会通过测试证明自己没有问题
- 基于Java Socket实现客户端/服务器功能，传输方式用TCP
- 客户端让用户输入中缀表达式，然后把中缀表达式调用MyBC.java的功能转化为后缀表达式，把后缀表达式用3DES或AES算法加密后通过网络把密文发送给服务器
- 服务器接收到后缀表达式表达式后，进行解密（和客户端协商密钥，可以用数组保存），然后调用MyDC.java的功能计算后缀表达式的值，把结果发送给客户端
- 客户端显示服务器发送过来的结果
- 上传测试结果截图和码云链接
实验代码
Client3.java
import java.io.*;
import java.net.*;
import java.util.Scanner;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
public class Client3 {
public static void main(String[] args) {
Scanner inn = new Scanner(System.in);
Socket mysocket;
DataInputStream in = null;
DataOutputStream out = null;
try{
mysocket = new Socket("192.168.56.1",2010);
in = new DataInputStream(mysocket.getInputStream());
out = new DataOutputStream(mysocket.getOutputStream());
KeyGenerator kg=KeyGenerator.getInstance("AES");
kg.init(128);
SecretKey k=kg.generateKey();
Cipher cp=Cipher.getInstance("AES");
cp.init(Cipher.ENCRYPT_MODE,k);
System.out.println("请输入运算式：");
String str = inn.nextLine();
String suffix = MyBC.transform(str);
byte[]ptext=suffix.getBytes();
byte[]ctext=cp.doFinal(ptext);
byte kb[] = k.getEncoded();
String str1 = Binary.parseByte2HexStr(ctext);
String str2 = Binary.parseByte2HexStr(kb);
out.writeUTF(str1);
out.writeUTF(str2);
String result = in.readUTF();
System.out.println("求值为："+result);
Thread.sleep(500);
}catch (Exception e){
System.out.println("服务器已断开"+e);
}
}
}
Sever3.java
import java.io.*;
import java.net.*;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.*;
public class Sever3 {
public static void main(String[] args) {
ServerSocket serverForClient = null;
Socket socketOnServer = null;
DataOutputStream out = null;
DataInputStream in = null;
MyDC myDC = new MyDC();
try{
serverForClient = new ServerSocket(2010);
}catch (IOException e){
System.out.println("端口已被占用"+e);
}
try{
System.out.println("等待客户呼叫");
socketOnServer = serverForClient.accept();
out = new DataOutputStream(socketOnServer.getOutputStream());
in = new DataInputStream(socketOnServer.getInputStream());
String str1= in.readUTF();
byte cipher[] = Binary.parseHexStr2Byte(str1);
System.out.println("收到密文："+str1);
String str2 = in.readUTF();
byte keyb[] = Binary.parseHexStr2Byte(str2);
Cipher cp=Cipher.getInstance("AES");
SecretKeySpec key = new SecretKeySpec(keyb,"AES");
cp.init(Cipher.DECRYPT_MODE,key);
byte []ptext=cp.doFinal(cipher);
String suffix = new String(ptext,"UTF8");
out.writeUTF(myDC.evaluate(suffix)+"");
Thread.sleep(500);
}catch (Exception e){
System.out.println("客户已断开"+e);
}
}
}
Binary.java
public class Binary {
public static String parseByte2HexStr(byte buf[]) {//二进制转换成十六进制
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) {//十六进制转化成二进制
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;
}
}
实验截图
任务四要求
- 1人负责客户端，1人负责服务器
- 注意责任归宿，要会通过测试证明自己没有问题
- 基于Java Socket实现客户端/服务器功能，传输方式用TCP
- 客户端让用户输入中缀表达式，然后把中缀表达式调用MyBC.java的功能转化为后缀表达式，把后缀表达式用3DES或AES算法加密通过网络把密文发送给服务器
- 客户端和服务器用DH算法进行3DES或AES算法的密钥交换
- 服务器接收到后缀表达式表达式后，进行解密，然后调用MyDC.java的功能计算后缀表达式的值，把结果发送给客户端
- 客户端显示服务器发送过来的结果
- 上传测试结果截图和码云链接
实验代码
Client4.java
import java.io.*;
import java.net.*;
import java.security.Key;
import java.util.Scanner;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
public class Client4 {
public static void main(String[] args) {
Scanner inn = new Scanner(System.in);
Socket mysocket;
DataInputStream in = null;
DataOutputStream out = null;
try{
mysocket = new Socket("192.168.56.1",2010);
in = new DataInputStream(mysocket.getInputStream());
out = new DataOutputStream(mysocket.getOutputStream());
KeyGenerator kg=KeyGenerator.getInstance("AES");
kg.init(128);
SecretKey k=kg.generateKey();
Cipher cp=Cipher.getInstance("AES");
cp.init(Cipher.ENCRYPT_MODE,k);
System.out.println("请输入运算式：");
String str = inn.nextLine();
String suffix = MyBC.transform(str);
byte[]ptext=suffix.getBytes();
byte[]ctext=cp.doFinal(ptext);
byte kb[] = k.getEncoded();
String str1 = Binary.parseByte2HexStr(ctext);
String str2 = Binary.parseByte2HexStr(kb);
out.writeUTF(str1);
out.writeUTF(str2);
Thread.sleep(500);
Key_DH.createPubAndPriKey("Clientpub.txt","Clientpri.txt");
FileInputStream fp = new FileInputStream("Clientpub.txt");
ObjectInputStream bp = new ObjectInputStream(fp);
Key kp = (Key) bp.readObject();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ObjectOutputStream oos = new ObjectOutputStream(baos);
oos.writeObject(kp);
byte[] kb1 = baos.toByteArray();
String PubKey1 = Binary.parseByte2HexStr(kb1);
out.writeUTF(PubKey1);
Thread.sleep(500);
String push = in.readUTF();
byte [] np1= Binary.parseHexStr2Byte(push);
ObjectInputStream ois = new ObjectInputStream (new ByteArrayInputStream (np1));
Key k2 = (Key)ois.readObject();;
FileOutputStream f2 = new FileOutputStream("Serverpub.txt");
ObjectOutputStream b2 = new ObjectOutputStream(f2);
b2.writeObject(k2);
Thread.sleep(500);
SecretKeySpec key = KeyAgre.createKey("Serverpub.txt", "Clientpri.txt");
String result = in.readUTF();
System.out.println("\n求值为："+result);
Thread.sleep(500);
}catch (Exception e){
System.out.println("服务器已断开"+e);
}
}
}
Sever4.java
import java.io.*;
import java.net.*;
import java.security.Key;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.*;
public class Sever4 {
public static void main(String[] args) {
ServerSocket serverForClient = null;
Socket socketOnServer = null;
DataOutputStream out = null;
DataInputStream in = null;
MyDC myDC = new MyDC();
try{
serverForClient = new ServerSocket(2010);
}catch (IOException e){
System.out.println("端口已被占用"+e);
}
try{
System.out.println("等待客户呼叫");
socketOnServer = serverForClient.accept();
out = new DataOutputStream(socketOnServer.getOutputStream());
in = new DataInputStream(socketOnServer.getInputStream());
String str1= in.readUTF();
byte cipher[] = Binary.parseHexStr2Byte(str1);
System.out.println("收到密文："+str1);
String str2 = in.readUTF();
byte keyb[] = Binary.parseHexStr2Byte(str2);
String PubKey = in.readUTF();
byte np[] = Binary.parseHexStr2Byte(PubKey);
Key_DH.createPubAndPriKey("Serverpub.txt","Serverpri.txt");
FileInputStream fp = new FileInputStream("Serverpub.txt");
ObjectInputStream bp = new ObjectInputStream(fp);
Key kp = (Key) bp.readObject();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ObjectOutputStream oos = new ObjectOutputStream(baos);
oos.writeObject(kp);
byte[] kb = baos.toByteArray();
String pop = Binary.parseByte2HexStr(kb);
out.writeUTF(pop);
Thread.sleep(500);
SecretKeySpec key = KeyAgre.createKey("Serverpub.txt","Clientpri.txt");
Cipher cp=Cipher.getInstance("AES");
SecretKeySpec key1 = new SecretKeySpec(keyb,"AES");
cp.init(Cipher.DECRYPT_MODE,key1);
byte []ptext=cp.doFinal(cipher);
String suffix = new String(ptext,"UTF8");
out.writeUTF(myDC.evaluate(suffix)+"");
Thread.sleep(500);
}catch (Exception e){
System.out.println("客户已断开"+e);
}
}
}
Key_DH.java
import java.io.*;
import java.math.*;
import java.security.*;
import java.security.spec.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import javax.crypto.interfaces.*;
public class Key_DH{
//三个静态变量的定义从
// C:\j2sdk-1_4_0-doc\docs\guide\security\jce\JCERefGuide.html
// 拷贝而来
// The 1024 bit Diffie-Hellman modulus values used by SKIP
private static final byte skip1024ModulusBytes[] = {
(byte)0xF4, (byte)0x88, (byte)0xFD, (byte)0x58,
(byte)0x4E, (byte)0x49, (byte)0xDB, (byte)0xCD,
(byte)0x20, (byte)0xB4, (byte)0x9D, (byte)0xE4,
(byte)0x91, (byte)0x07, (byte)0x36, (byte)0x6B,
(byte)0x33, (byte)0x6C, (byte)0x38, (byte)0x0D,
(byte)0x45, (byte)0x1D, (byte)0x0F, (byte)0x7C,
(byte)0x88, (byte)0xB3, (byte)0x1C, (byte)0x7C,
(byte)0x5B, (byte)0x2D, (byte)0x8E, (byte)0xF6,
(byte)0xF3, (byte)0xC9, (byte)0x23, (byte)0xC0,
(byte)0x43, (byte)0xF0, (byte)0xA5, (byte)0x5B,
(byte)0x18, (byte)0x8D, (byte)0x8E, (byte)0xBB,
(byte)0x55, (byte)0x8C, (byte)0xB8, (byte)0x5D,
(byte)0x38, (byte)0xD3, (byte)0x34, (byte)0xFD,
(byte)0x7C, (byte)0x17, (byte)0x57, (byte)0x43,
(byte)0xA3, (byte)0x1D, (byte)0x18, (byte)0x6C,
(byte)0xDE, (byte)0x33, (byte)0x21, (byte)0x2C,
(byte)0xB5, (byte)0x2A, (byte)0xFF, (byte)0x3C,
(byte)0xE1, (byte)0xB1, (byte)0x29, (byte)0x40,
(byte)0x18, (byte)0x11, (byte)0x8D, (byte)0x7C,
(byte)0x84, (byte)0xA7, (byte)0x0A, (byte)0x72,
(byte)0xD6, (byte)0x86, (byte)0xC4, (byte)0x03,
(byte)0x19, (byte)0xC8, (byte)0x07, (byte)0x29,
(byte)0x7A, (byte)0xCA, (byte)0x95, (byte)0x0C,
(byte)0xD9, (byte)0x96, (byte)0x9F, (byte)0xAB,
(byte)0xD0, (byte)0x0A, (byte)0x50, (byte)0x9B,
(byte)0x02, (byte)0x46, (byte)0xD3, (byte)0x08,
(byte)0x3D, (byte)0x66, (byte)0xA4, (byte)0x5D,
(byte)0x41, (byte)0x9F, (byte)0x9C, (byte)0x7C,
(byte)0xBD, (byte)0x89, (byte)0x4B, (byte)0x22,
(byte)0x19, (byte)0x26, (byte)0xBA, (byte)0xAB,
(byte)0xA2, (byte)0x5E, (byte)0xC3, (byte)0x55,
(byte)0xE9, (byte)0x2F, (byte)0x78, (byte)0xC7
};
// The SKIP 1024 bit modulus
private static final BigInteger skip1024Modulus
= new BigInteger(1, skip1024ModulusBytes);
// The base used with the SKIP 1024 bit modulus
private static final BigInteger skip1024Base = BigInteger.valueOf(2);
public static void createPubAndPriKey(String s1,String s2) throws Exception{
DHParameterSpec DHP=
new DHParameterSpec(skip1024Modulus,skip1024Base);
KeyPairGenerator kpg= KeyPairGenerator.getInstance("DH");
kpg.initialize(DHP);
KeyPair kp=kpg.genKeyPair();
PublicKey pbk=kp.getPublic();
PrivateKey prk=kp.getPrivate();
// 保存公钥
FileOutputStream f1=new FileOutputStream(s1);
ObjectOutputStream b1=new ObjectOutputStream(f1);
b1.writeObject(pbk);
// 保存私钥
FileOutputStream f2=new FileOutputStream(s2);
ObjectOutputStream b2=new ObjectOutputStream(f2);
b2.writeObject(prk);
}
}
KeyAgre.java
import java.io.*;
import java.security.*;
import javax.crypto.*;
import javax.crypto.spec.*;
public class KeyAgre{
public static SecretKeySpec createKey(String s1, String s2) throws Exception{
// 读取对方的DH公钥
FileInputStream f1=new FileInputStream(s1);
ObjectInputStream b1=new ObjectInputStream(f1);
PublicKey pbk=(PublicKey)b1.readObject( );
//读取自己的DH私钥
FileInputStream f2=new FileInputStream(s2);
ObjectInputStream b2=new ObjectInputStream(f2);
PrivateKey prk=(PrivateKey)b2.readObject( );
// 执行密钥协定
KeyAgreement ka=KeyAgreement.getInstance("DH");
ka.init(prk);
ka.doPhase(pbk,true);
//生成共享信息
System.out.println("共享信息为：");
byte[] sb=ka.generateSecret();
for(int i=0;i<sb.length;i++){
System.out.print(sb[i]+" ");
}
SecretKeySpec k=new SecretKeySpec(sb,"DESede");
return k;
}
}
实验截图
任务五要求
- 1人负责客户端，1人负责服务器
- 注意责任归宿，要会通过测试证明自己没有问题
- 基于Java Socket实现客户端/服务器功能，传输方式用TCP
- 客户端让用户输入中缀表达式，然后把中缀表达式调用MyBC.java的功能转化为后缀表达式，把后缀表达式用3DES或AES算法加密通过网络把密文和明文的MD5値发送给服务器
- 客户端和服务器用DH算法进行3DES或AES算法的密钥交换
- 服务器接收到后缀表达式表达式后，进行解密，解密后计算明文的MD5值，和客户端传来的MD5进行比较，一致则调用MyDC.java的功能计算后缀表达式的值，把结果发送给客户端
- 客户端显示服务器发送过来的结果
- 上传测试结果截图和码云链接
实验代码
Client5.java
import java.io.*;
import java.net.*;
import java.security.Key;
import java.util.Scanner;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
public class Client5 {
public static void main(String[] args) {
Scanner inn = new Scanner(System.in);
Socket mysocket;
DataInputStream in = null;
DataOutputStream out = null;
try{
mysocket = new Socket("192.168.56.1",2010);
in = new DataInputStream(mysocket.getInputStream());
out = new DataOutputStream(mysocket.getOutputStream());
KeyGenerator kg=KeyGenerator.getInstance("AES");
kg.init(128);
SecretKey k=kg.generateKey();
Cipher cp=Cipher.getInstance("AES");
cp.init(Cipher.ENCRYPT_MODE,k);
System.out.println("请输入运算式：");
String str = inn.nextLine();
String suffix = MyBC.transform(str);
byte[]ptext=suffix.getBytes();
byte[]ctext=cp.doFinal(ptext);
byte kb[] = k.getEncoded();
String str1 = Binary.parseByte2HexStr(ctext);
String str2 = Binary.parseByte2HexStr(kb);
out.writeUTF(str1);
out.writeUTF(str2);
Thread.sleep(500);
Key_DH.createPubAndPriKey("Clientpub.txt","Clientpri.txt");
FileInputStream fp = new FileInputStream("Clientpub.txt");
ObjectInputStream bp = new ObjectInputStream(fp);
Key kp = (Key) bp.readObject();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ObjectOutputStream oos = new ObjectOutputStream(baos);
oos.writeObject(kp);
byte[] kb1 = baos.toByteArray();
String PubKey1 = Binary.parseByte2HexStr(kb1);
out.writeUTF(PubKey1);
Thread.sleep(500);
String push = in.readUTF();
byte [] np1= Binary.parseHexStr2Byte(push);
ObjectInputStream ois = new ObjectInputStream (new ByteArrayInputStream (np1));
Key k2 = (Key)ois.readObject();;
FileOutputStream f2 = new FileOutputStream("Serverpub.txt");
ObjectOutputStream b2 = new ObjectOutputStream(f2);
b2.writeObject(k2);
Thread.sleep(500);
SecretKeySpec key = KeyAgre.createKey("Serverpub.txt", "Clientpri.txt");
String clientMD5 = DigestPass.digestPass(suffix);
System.out.println("明文MD5值为："+ clientMD5);
out.writeUTF(clientMD5);
Thread.sleep(500);
String result = in.readUTF();
System.out.println("求值为："+result);
Thread.sleep(500);
}catch (Exception e){
System.out.println("服务器已断开"+e);
}
}
}
Sever5.java
import java.io.*;
import java.net.*;
import java.security.Key;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.*;
public class Sever5 {
public static void main(String[] args) {
ServerSocket serverForClient = null;
Socket socketOnServer = null;
DataOutputStream out = null;
DataInputStream in = null;
MyDC myDC = new MyDC();
try{
serverForClient = new ServerSocket(2010);
}catch (IOException e){
System.out.println("端口已被占用"+e);
}
try{
System.out.println("等待客户呼叫");
socketOnServer = serverForClient.accept();
out = new DataOutputStream(socketOnServer.getOutputStream());
in = new DataInputStream(socketOnServer.getInputStream());
String str1= in.readUTF();
byte cipher[] = Binary.parseHexStr2Byte(str1);
System.out.println("收到密文："+str1);
String str2 = in.readUTF();
byte keyb[] = Binary.parseHexStr2Byte(str2);
String PubKey = in.readUTF();
byte np[] = Binary.parseHexStr2Byte(PubKey);
Key_DH.createPubAndPriKey("Serverpub.txt","Serverpri.txt");
FileInputStream fp = new FileInputStream("Serverpub.txt");
ObjectInputStream bp = new ObjectInputStream(fp);
Key kp = (Key) bp.readObject();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ObjectOutputStream oos = new ObjectOutputStream(baos);
oos.writeObject(kp);
byte[] kb = baos.toByteArray();
String pop = Binary.parseByte2HexStr(kb);
out.writeUTF(pop);
Thread.sleep(500);
SecretKeySpec key = KeyAgre.createKey("Serverpub.txt","Clientpri.txt");
Cipher cp=Cipher.getInstance("AES");
SecretKeySpec key1 = new SecretKeySpec(keyb,"AES");
cp.init(Cipher.DECRYPT_MODE,key1);
byte []ptext=cp.doFinal(cipher);
String suffix = new String(ptext,"UTF8");
String serverMD5 = DigestPass.digestPass(suffix);
System.out.println("解密的MD5值为："+serverMD5);
String clientMD5 = in.readUTF();
if(serverMD5.equals(clientMD5)) {
System.out.println("两组MD5值相等");
out.writeUTF(myDC.evaluate(suffix) + "");
}
Thread.sleep(500);
}catch (Exception e){
System.out.println("客户已断开"+e);
}
}
}
DigestPass.java
import java.security.*;
public class DigestPass{
public static String digestPass(String x) throws Exception{
MessageDigest m=MessageDigest.getInstance("MD5");
m.update(x.getBytes("UTF8"));
byte s[ ]=m.digest( );
String result="";
for (int i=0; i<s.length; i++){
result+=Integer.toHexString((0x000000ff & s[i]) |
0xffffff00).substring(6);
}
System.out.println(result);
return result;
}
}
实验截图
