天津理工大学信息安全综合实验4.1

天津理工大学信息安全综合实验4.1

需求： 使用 Java Security 或其它语言开发一个安全通信软件
要求：本实验应用 DES，RSA，MD5 等加密算法，以及 Socket 套接字实现一个简单的加密解密的聊天工具 CryptTalk。程序的步骤基本如下：首先，服务器端随机产生一对 RSA 密钥，将公钥发送给客户端，客户端将自己的对称密钥用公钥加密发送给服务器端，服务器端接收到加密后的密钥后，用自己的私钥解密得到对称密钥。然后服务器端和客户端都利用这个对称密钥对发送的消息加密，进行加密后的聊天。同时把消息经过 MD5 加密生成摘要发送，在接收端解密后进行 MD5 加密比较，检查信息是否被篡改。
流程图（上半部分为服务端操作，下半部分为客户端操作）

开发语言Python（世界上最好的语言 ）

服务端

# 服务端
import socket
import tkinter as tk
import rsa
from tkinter import scrolledtext
import threading
from pyDes import des, CBC, PAD_PKCS5
import binascii
import hashlib

global conn
global pubkey
global privkey
des_str = ''
des_key = ''
msg_out = ''
server = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
server.bind(("localhost",6969)) # 绑定要监听的端口
server.listen(5) # 开始监听 表示可以使用五个链接排队
# 发送rsa数据
def send_rsa():
    global conn
    global pubkey
    global privkey
    (pubkey, privkey) = rsa.newkeys(1024)
    print('发送的rsa公钥：',pubkey)
    pub = pubkey.save_pkcs1().decode()
    conn.send(pub.encode())
# 接受des数据
def recv_des():
    global des_str
    global privkey
    global des_key
    des_m = conn.recv(1024)
    print('\n接受到加密的des密码：',des_m)
    des_str = rsa.decrypt(des_m, privkey).decode()
    print('\n私钥解密后的des密码：',des_str)
    if len(des_str) > 8:
        des_key = des_str[:8]
    else:
        des_key = des_str + (8-len(des_str))*'0'
    print('\ndes_key:',des_key)
    # 开启线程接受消息
    t = threading.Thread(target = get_msg)
    t.start()
# 获取消息
def get_msg():
    global scr
    global conn
    global msg_in
    while True:
        # 接受密文
        msg_in = conn.recv(1024)
        print('\nc2s:',msg_in)
        scr.insert('end','（密文）client:'+str(msg_in)[2:-1]+'\n') 
        # des解密
        msg_in=des_descrypt(msg_in).decode()
        print('client:',msg_in)
        scr.insert('end','（明文）client:'+msg_in+'\n')
        # MD5
        md5_msg = msg_in
        md5 = hashlib.md5()
        md5.update(md5_msg.encode('utf-8'))
        print('c_MD5:',md5.hexdigest())
        scr.insert('end','（MD5）client:'+md5.hexdigest()+'\n\n')
# des加密
def des_encrypt(s):
    global des_key
    secret_key = des_key
    iv = secret_key
    k = des(secret_key, CBC, iv, pad=None, padmode=PAD_PKCS5)
    en = k.encrypt(s, padmode=PAD_PKCS5)
    return binascii.b2a_hex(en)
# des解密
def des_descrypt(s):
    global des_key
    secret_key = des_key
    iv = secret_key
    k = des(secret_key, CBC, iv, pad=None, padmode=PAD_PKCS5)
    de = k.decrypt(binascii.a2b_hex(s), padmode=PAD_PKCS5)
    return de
# __mian__
win = tk.Tk()
win.title('CryptTalk服务端')  # 名称
win.geometry('500x300+200+200')  # 窗口大小1
frame = tk.Frame(win,width=450, height=300)
frame.pack()
frame_l = tk.Frame(frame, width=300, height=300)# 第二层frame，左frame，长在主frame上
frame_r = tk.Frame(frame, width=150, height=300)# 第二层frame，右frame，长在主frame上
frame_l.pack(side='left')
frame_r.pack(side='right')
l1 = tk.Label(frame_l, text='消息窗口                           ', font=('宋体', 10), width=40,height=2)
l1.pack()
scr = scrolledtext.ScrolledText(frame_l, bg='white', fg='black', font=('宋体', 12), width=30, height=10)
scr.pack()
l3 = tk.Label(frame_l, width=30, height=1)
l3.pack()
l4 = tk.Entry(frame_l, show=None, font=('宋体', 12),width=30)
l4.pack()
l3.pack()
def fasong():
    global conn
    global msg_out
    # 原文
    msg_out = l4.get()
    print("\nme:",msg_out)
    scr.insert('end','（明文）me:'+msg_out+'\n')
    # MD5
    md5_msg = msg_out
    md5 = hashlib.md5()
    md5.update(md5_msg.encode('utf-8'))
    print('m_MD5:',md5.hexdigest())
    scr.insert('end','（MD5）me:'+md5.hexdigest()+'\n')
    # des加密
    msg_out = msg_out.encode('utf-8')
    msg_out = des_encrypt(msg_out)
    scr.insert('end','（密文）me:'+str(msg_out)[2:-1]+'\n\n')
    print('（密文）me:',msg_out)
    # 发送
    conn.send(msg_out)
b1 = tk.Button(frame_l, text='发送', font=('宋体', 12), width=10, height=1, command=fasong)
b1.pack()
r1 = tk.Label(frame_r, text='DES密码', font=('宋体', 12), width=20, height=2)
r1.pack()
var2 = tk.StringVar()
l2 = tk.Label(frame_r, textvariable=var2, bg='white', fg='black', font=('宋体', 12), width=20, height=2)
l2.pack()
b2 = tk.Button(frame_r, text='发送RSA公钥', font=('宋体', 10), width=10, height=2, command=send_rsa)
b2.pack()
b3 = tk.Button(frame_r, text='接受DES秘钥', font=('宋体', 10), width=10, height=2, command=recv_des)
b3.pack()
def refreshText():
    global des_str
    if des_str != '':
        var2.set(des_str)
        l2.pack()
    win.after(1000,refreshText)
win.after(1000,refreshText)
while True:
    conn,addr = server.accept() # 等待链接,多个链接的时候就会出现问题,其实返回了两个值
    try:
        win.iconbitmap('1.ico')   # 更改窗口图标
        win.mainloop()# 主窗口循环显示
    except ConnectionResetError as e:
        print("关闭了正在占线的链接！")
        break    
# 关闭当前端口
conn.shutdown()
conn.close()

客户端

# 客户端
import socket  
import tkinter as tk
import rsa
from tkinter import scrolledtext
import threading
from pyDes import des, CBC, PAD_PKCS5
import binascii
import hashlib

global pubkey_str
global pubkey
global client
msg_out = ''
client = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
client.connect(("localhost", 6969))  # 建立一个链接，连接到本地的6969端口
# des加密
def des_encrypt(s):
    global des_key
    secret_key = des_key
    iv = secret_key
    k = des(secret_key, CBC, iv, pad=None, padmode=PAD_PKCS5)
    en = k.encrypt(s, padmode=PAD_PKCS5)
    return binascii.b2a_hex(en)
# des解密
def des_descrypt(s):
    global des_key
    secret_key = des_key
    iv = secret_key
    k = des(secret_key, CBC, iv, pad=None, padmode=PAD_PKCS5)
    de = k.decrypt(binascii.a2b_hex(s), padmode=PAD_PKCS5)
    return de
# 接受数据
def get_msg():
    global scr
    global client
    global msg_in
    while True:
        # 接受密文
        msg_in = client.recv(1024)
        print('\ns2c:',msg_in)
        scr.insert('end','（密文）server:'+str(msg_in)[2:-1]+'\n')
        # des解密
        msg_in=des_descrypt(msg_in).decode()
        print('server:',msg_in)
        scr.insert('end','（明文）server:'+msg_in+'\n') 
        # MD5
        md5_msg = msg_in
        md5 = hashlib.md5()
        md5.update(md5_msg.encode('utf-8'))
        print('s_MD5:',md5.hexdigest())
        scr.insert('end','（MD5）server:'+md5.hexdigest()+'\n\n')        
# __mian__
win = tk.Tk()
win.title('CryptTalk客户端')  # 名称
win.geometry('500x300+800+200')  # 窗口大小
frame = tk.Frame(win,width=450, height=300)
frame.pack()
frame_l = tk.Frame(frame, width=300, height=300)# 第二层frame，左frame，长在主frame上
frame_r = tk.Frame(frame, width=150, height=300)# 第二层frame，右frame，长在主frame上
frame_l.pack(side='left')
frame_r.pack(side='right')
l1 = tk.Label(frame_l, text='消息窗口                           ', font=('宋体', 10), width=40,height=2)
l1.pack()
scr = scrolledtext.ScrolledText(frame_l, bg='white', fg='black', font=('宋体', 12), width=30, height=10)
scr.pack()
l3 = tk.Label(frame_l, width=30, height=1)
l3.pack()
l4 = tk.Entry(frame_l, show=None, font=('宋体', 12),width=30)
l4.pack()
l3.pack()
# 发送消息
def fasong():
    global client
    global msg_out
    # 原文
    msg_out = l4.get()
    print("\nme:",msg_out)
    scr.insert('end','（明文）me:'+msg_out+'\n')
    # MD5
    md5_msg = msg_out
    md5 = hashlib.md5()
    md5.update(md5_msg.encode('utf-8'))
    print('m_MD5:',md5.hexdigest())
    scr.insert('end','（MD5）me:'+md5.hexdigest()+'\n')
    # des加密
    msg_out =msg_out.encode('utf-8')
    msg_out = des_encrypt(msg_out)
    scr.insert('end','（密文）me:'+str(msg_out)[2:-1]+'\n\n')
    print('c2s:',msg_out)
    # 发送
    client.send(msg_out)
b1 = tk.Button(frame_l, text='发送', font=('宋体', 12), width=10, height=1, command=fasong)
b1.pack()
r1 = tk.Label(frame_r, text='DES密码', font=('宋体', 12), width=20, height=2)
r1.pack()
r2 = tk.Entry(frame_r, show=None, font=('宋体', 12),width=20)
r2.pack()
# 加密后发送des密码
def send_des():
    global pubkey
    global pubkey_str
    global num
    global client
    global des_key
    msg = r2.get()
    print('输入的des密码：',msg)
    pubkey = rsa.PublicKey.load_pkcs1(pubkey_str.encode())
    print('\n接受到的rsa公钥：',pubkey)
    crypto = rsa.encrypt(msg.encode("utf-8"), pubkey)
    print('\n加密后发送的des密码：',crypto)
    client.send(crypto)
    if len(msg) > 8:
        des_key = msg[:8]
    else:
        des_key = msg + (8-len(msg))*'0'
    print('\ndes_key:',des_key)
    # 开启线程接受消息
    t = threading.Thread(target = get_msg)
    t.start()
b2 = tk.Button(frame_r, text='发送DES密码', font=('宋体', 10), width=10, height=2, command=send_des)
b2.pack()
while True:
    pubkey_str = client.recv(1024).decode()
    win.iconbitmap('1.ico')   # 更改窗口图标
    win.mainloop()# 主窗口循环显示
client.close()  # 关闭这个链接