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			261 lines
		
	
	
		
			10 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
---
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layout: post
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title: 加密传输Demo V2
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tags: [加密, Demo]
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--- 
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  太业余总感觉不太好啊<!--more-->    
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# 前言
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  在上个月我写了一个[加密传输的Demo](/2020/05/29/encrypt.html),相当的业余,这个东西只能做到从客户端向服务端的单向传输,而且因为只有一次请求,所以中间人攻击也非常的容易。   
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  虽然我觉得那个应该足够我完成作业了,但是我想了想,太业余总显得我很菜 ~~(难道不是吗?)~~ ,所以我打算还是努力一下把完整的握手也做出来吧。   
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# 实现思路
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  和上次差不多,同样我打算通过RSA加密一个随机数作为AES的密钥,但是和上次不同,这次的这个密钥将在通信建立之后密钥就不再变化,传入传出都是这个密钥。   
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  之前觉得握手阶段可能很麻烦,不过我画了一下图稍微理了理思路发现其实也没多复杂,也就是客户端生成密钥然后加密传输过来让服务端保存,完成之后之间的传输只要传被加密的数据就行了。这样我觉得应该也能起到一定的防止中间人攻击的作用吧……     
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  不过我只用了一个文件作为传输的管道,为了避免冲突,我在每次写入数据的时候也都标明了数据的来源,这样就不会因为自己刚发完然后自己又重新接收自己发的东西了。   
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  另外老师希望我的Demo有个简单的应用,所以我又另外加了一个极其简单的登录系统在里面,这样我就不用手动操作服务端了。
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# 代码
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## server.py
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```python
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# -*- coding: utf-8 -*-
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print("加密通道服务端演示开始")
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from Crypto.PublicKey import RSA
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from Crypto.Cipher import PKCS1_v1_5
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from Crypto.Cipher import AES  
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import base64
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import hashlib
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import json
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import time
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private_key = """-----BEGIN RSA PRIVATE KEY-----
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MIICXQIBAAKBgQDfEQ82qUrto7h4BL3TsA/DFXSdM44cbeY4kPccD7gLGhaZRClz
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YKIh5zYdfjBGF+0HXfMa1u9b7GNs2AjVIsx8Kx0QLnMfmtkmGWGhOXz/9IDLKJOx
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0weKv61gysKItgzVKn2mbLool4R/PQBc3AjDyHw+io1KpVz+3kRTaGs1fQIDAQAB
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AoGAWB4kFWLA/6k6OOcemd4mC9mQ7HyuOdrMJDJX+5TWDkSrArajbTmSMrRkczgj
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F71h3BQn8cVQXs695ARfUNrjTbi2Y0LjN7ScK7ExzTLdoMEFw5JsHggJZ0zBQY6w
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mwOdGfqzA6tZPXgkn+jqEha+CD6GrwnTM1oDGJC/aKG2OmECQQDkO9IhUhFc/PSU
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0zvGE6AOcqk5wlOuvMg+oAFHJHJZ9XW7+X/Nx0ZoVDFq/cZQj+46t+fiwUwhdW7l
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IfCvNGKFAkEA+jRQmWGKrbf1ns4S0SezJvysd5O6otRGJXr+Ex2uDhc39ZTeUsyg
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kjrLhp8STLMOmql+8g5fghct17EuCX1EmQJBAJz9BNnEkIrst/OSpH/nyeWGOx6u
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q077LaXd+2MLD9kO/O/Se3V5B9YFa4STkJCjoBMloswXd51gIGpdgSeSmd0CQQCL
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PrwwcGmWfo+ynqs4PajlpK9zKQMwhYS4bTejedwZOXDKOtx0Ji+i0hfcxwCPMQOK
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rZPZsIgUxUOdC508aLvZAkBDkHxunCzDm0w4DdTUN7S9YSpVvQEjK/xUQiWaKV12
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8QgskhU2DNdYK2NxifnWrKtx3uQmqMxX5aLuJZ4493yr
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-----END RSA PRIVATE KEY-----"""
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# 公钥解密
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def rsa_decode(cipher_text, private_key):
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    rsakey = RSA.importKey(private_key)  # 导入读取到的私钥
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    cipher = PKCS1_v1_5.new(rsakey)  # 生成对象
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    # 将密文解密成明文,返回的是一个bytes类型数据,需要自己转换成str
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    text = cipher.decrypt(base64.b64decode(cipher_text), "ERROR")
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    return text.decode()
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class PrpCrypt(object):
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    def __init__(self, key):
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        self.key = key.encode('utf-8')
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        self.mode = AES.MODE_CBC
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    def encrypt(self, text):
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        text = text.encode('utf-8')
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        cryptor = AES.new(self.key, self.mode, b'0000000000000000')
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        # 这里密钥key 长度必须为16(AES-128),
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        # 24(AES-192),或者32 (AES-256)Bytes 长度
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        # 目前AES-128 足够目前使用
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        length = 16
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        count = len(text)
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        if count < length:
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            add = (length - count)
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            # \0 backspace
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            # text = text + ('\0' * add)
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            text = text + ('\0' * add).encode('utf-8')
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        elif count > length:
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            add = (length - (count % length))
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            # text = text + ('\0' * add)
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            text = text + ('\0' * add).encode('utf-8')
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        self.ciphertext = cryptor.encrypt(text)
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        # 因为AES加密时候得到的字符串不一定是ascii字符集的,输出到终端或者保存时候可能存在问题
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        # 所以这里统一把加密后的字符串转化为16进制字符串
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        return base64.b64encode(self.ciphertext)
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    # 解密后,去掉补足的空格用strip() 去掉
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    def decrypt(self, text):
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        cryptor = AES.new(self.key, self.mode, b'0000000000000000')
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        plain_text = cryptor.decrypt(base64.b64decode(text))
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        # return plain_text.rstrip('\0')
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        return bytes.decode(plain_text).rstrip('\0')
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#初始化pipe
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file = open('pipe.txt','w')
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print("",file = file)
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file.close()
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#协商密钥
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while True:
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    pipe = open("pipe.txt", mode='r')
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    data = pipe.read()
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    if not data == "\n":
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        data = json.loads(data)
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        pipe.close()
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        break
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    pipe.close()
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    time.sleep(1)
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file = open('pipe.txt','w')
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print("",file = file)
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file.close()
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key = rsa_decode(data["key"], private_key)
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akey = PrpCrypt(key)
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print("成功获取密钥",key)
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print("已建立连接")
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userInfo={"Name":"Mayx","Passwd":'25d55ad283aa400af464c76d713c07ad',"Book":"《会说话就多说点》,《在哪里能买到您的著作》"}
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#处理阶段
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#Waiting for Quest
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while True:
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    pipe = open("pipe.txt", mode='r')
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    data = pipe.read()
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    if not data == "\n":
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        data = json.loads(data)
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        if data["from"] == "Client":
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            pipe.close()
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            break
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    pipe.close()
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    time.sleep(1)
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print("已收到请求")
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data = json.loads(akey.decrypt(data["data"]))
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if data["name"] == userInfo["Name"] and data["pwd"] == userInfo["Passwd"]:
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    file = open('pipe.txt','w')
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    print(json.dumps({"from":"Server","data":akey.encrypt("登录成功,您的书单如下:"+userInfo["Book"]).decode("utf-8")}),file = file)
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    file.close()
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else:
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    file = open('pipe.txt','w')
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    print(json.dumps({"from":"Server","data":akey.encrypt("登录失败").decode("utf-8")}),file = file)
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    file.close()
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print("请求已回应")
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print("加密通道服务端演示结束")
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```
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## client.py
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```python
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# -*- coding: utf-8 -*-
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print("加密通道客户端演示开始")
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import random
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from Crypto.PublicKey import RSA
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from Crypto.Cipher import PKCS1_v1_5
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from Crypto.Cipher import AES  
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import base64
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import hashlib
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import json
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import time
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public_key = """-----BEGIN PUBLIC KEY-----
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MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDfEQ82qUrto7h4BL3TsA/DFXSd
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M44cbeY4kPccD7gLGhaZRClzYKIh5zYdfjBGF+0HXfMa1u9b7GNs2AjVIsx8Kx0Q
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LnMfmtkmGWGhOXz/9IDLKJOx0weKv61gysKItgzVKn2mbLool4R/PQBc3AjDyHw+
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io1KpVz+3kRTaGs1fQIDAQAB
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-----END PUBLIC KEY-----
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"""
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# 公钥加密
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def rsa_encode(message, public_key):
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    rsakey = RSA.importKey(public_key)  # 导入读取到的公钥
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    cipher = PKCS1_v1_5.new(rsakey)  # 生成对象
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    # 通过生成的对象加密message明文,注意,在python3中加密的数据必须是bytes类型的数据,不能是str类型的数据
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    cipher_text = base64.b64encode(cipher.encrypt(message.encode(encoding="utf-8")))
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    # 公钥每次加密的结果不一样跟对数据的padding(填充)有关
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    return cipher_text.decode()
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class PrpCrypt(object):
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    def __init__(self, key):
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        self.key = key.encode('utf-8')
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        self.mode = AES.MODE_CBC
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    # 加密函数,如果text不足16位就用空格补足为16位,
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    # 如果大于16当时不是16的倍数,那就补足为16的倍数。
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    def encrypt(self, text):
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        text = text.encode('utf-8')
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        cryptor = AES.new(self.key, self.mode, b'0000000000000000')
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        # 这里密钥key 长度必须为16(AES-128),
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        # 24(AES-192),或者32 (AES-256)Bytes 长度
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        # 目前AES-128 足够目前使用
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        length = 16
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        count = len(text)
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        if count < length:
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            add = (length - count)
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            # \0 backspace
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            # text = text + ('\0' * add)
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            text = text + ('\0' * add).encode('utf-8')
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        elif count > length:
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            add = (length - (count % length))
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            # text = text + ('\0' * add)
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            text = text + ('\0' * add).encode('utf-8')
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        self.ciphertext = cryptor.encrypt(text)
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        # 因为AES加密时候得到的字符串不一定是ascii字符集的,输出到终端或者保存时候可能存在问题
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        # 所以这里统一把加密后的字符串转化为16进制字符串
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        return base64.b64encode(self.ciphertext)
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        # 解密后,去掉补足的空格用strip() 去掉
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    def decrypt(self, text):
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        cryptor = AES.new(self.key, self.mode, b'0000000000000000')
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        plain_text = cryptor.decrypt(base64.b64decode(text))
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        # return plain_text.rstrip('\0')
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        return bytes.decode(plain_text).rstrip('\0')
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#初始化阶段
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while True:
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    try:
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        pipe = open("pipe.txt", mode='r')
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    except:
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        time.sleep(1)
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    else:
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        break
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pipe.close()
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#协商密钥
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key = str(random.randint(1000000000000000,9999999999999999))
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akey = PrpCrypt(key)
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cipher = rsa_encode(key, public_key)
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data = json.dumps({"key":cipher})
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file = open('pipe.txt','w')
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print(data,file = file)
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file.close()
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while True:
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    pipe = open("pipe.txt", mode='r')
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    if pipe.read() == "\n":
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        pipe.close()
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        break
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    pipe.close()
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    time.sleep(1)
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print("成功发送密钥",key)
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print("已建立连接")
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#处理阶段
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#Single Quest
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name = input("请输入用户名:")
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pwd = input("请输入密码:")
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hash = hashlib.md5(pwd.encode(encoding='UTF-8')).hexdigest()
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data = json.dumps({"from":"Client","data":akey.encrypt(json.dumps({"name":name,"pwd":hash})).decode("utf-8")})
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file = open('pipe.txt','w')
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print(data,file = file)
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file.close()
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print("已发出,等待回应")
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while True:
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    pipe = open("pipe.txt", mode='r')
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    data = pipe.read()
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    if not data == "\n":
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        data = json.loads(data)
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        if data["from"] == "Server":
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            pipe.close()
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            break
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    pipe.close()
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    time.sleep(1)
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print("已收到回应")
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data = akey.decrypt(data["data"])
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print(data)
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print("加密通道客户端演示结束")
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```
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# 后记
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  关于SSL/TLS的具体内容我也没有好好看一遍,我打算回头有时间仔细看一看,然后再回来看这个代码是有多么的糟糕🤪。
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