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+---
+layout: post
+title: 加密传输Demo V2
+tags: [加密, Demo]
+--- 
+  太业余总感觉不太好啊<!--more-->    
+
+# 前言
+  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。   
+  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。   
+
+# 实现思路
+  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。   
+  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……     
+  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。   
+  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。
+  
+# 代码
+## server.py
+```python
+# -*- coding: utf-8 -*-
+print("加密通道服务端演示开始")
+from Crypto.PublicKey import RSA
+from Crypto.Cipher import PKCS1_v1_5
+from Crypto.Cipher import AES  
+import base64
+import hashlib
+import json
+import time
+
+private_key = """-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----"""
+
+# 公钥解密
+def rsa_decode(cipher_text, private_key):
+    rsakey = RSA.importKey(private_key)  # 导入读取到的私钥
+    cipher = PKCS1_v1_5.new(rsakey)  # 生成对象
+    # 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
+    text = cipher.decrypt(base64.b64decode(cipher_text), "ERROR")
+    return text.decode()
+    
+class PrpCrypt(object):
+ 
+    def __init__(self, key):
+        self.key = key.encode('utf-8')
+        self.mode = AES.MODE_CBC
+        
+    def encrypt(self, text):
+        text = text.encode('utf-8')
+        cryptor = AES.new(self.key, self.mode, b'0000000000000000')
+        # 这里密钥key 长度必须为16（AES-128）,
+        # 24（AES-192）,或者32 （AES-256）Bytes 长度
+        # 目前AES-128 足够目前使用
+        length = 16
+        count = len(text)
+        if count < length:
+            add = (length - count)
+            # \0 backspace
+            # text = text + ('\0' * add)
+            text = text + ('\0' * add).encode('utf-8')
+        elif count > length:
+            add = (length - (count % length))
+            # text = text + ('\0' * add)
+            text = text + ('\0' * add).encode('utf-8')
+        self.ciphertext = cryptor.encrypt(text)
+        # 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
+        # 所以这里统一把加密后的字符串转化为16进制字符串
+        return base64.b64encode(self.ciphertext)
+ 
+    # 解密后，去掉补足的空格用strip() 去掉
+    def decrypt(self, text):
+        cryptor = AES.new(self.key, self.mode, b'0000000000000000')
+        plain_text = cryptor.decrypt(base64.b64decode(text))
+        # return plain_text.rstrip('\0')
+        return bytes.decode(plain_text).rstrip('\0')
+
+#初始化pipe
+file = open('pipe.txt','w')
+print("",file = file)
+file.close()
+#协商密钥
+while True:
+    pipe = open("pipe.txt", mode='r')
+    data = pipe.read()
+    if not data == "\n":
+        data = json.loads(data)
+        pipe.close()
+        break
+    pipe.close()
+    time.sleep(1)
+file = open('pipe.txt','w')
+print("",file = file)
+file.close()
+key = rsa_decode(data["key"], private_key)
+akey = PrpCrypt(key)
+print("成功获取密钥",key)
+print("已建立连接")
+userInfo={"Name":"Mayx","Passwd":'25d55ad283aa400af464c76d713c07ad',"Book":"《会说话就多说点》，《在哪里能买到您的著作》"}
+
+#处理阶段
+#Waiting for Quest
+while True:
+    pipe = open("pipe.txt", mode='r')
+    data = pipe.read()
+    if not data == "\n":
+        data = json.loads(data)
+        if data["from"] == "Client":
+            pipe.close()
+            break
+    pipe.close()
+    time.sleep(1)
+print("已收到请求")
+data = json.loads(akey.decrypt(data["data"]))
+if data["name"] == userInfo["Name"] and data["pwd"] == userInfo["Passwd"]:
+    file = open('pipe.txt','w')
+    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)
+    file.close()
+else:
+    file = open('pipe.txt','w')
+    print(json.dumps({"from":"Server","data":akey.encrypt("登录失败").decode("utf-8")}),file = file)
+    file.close()
+print("请求已回应")
+print("加密通道服务端演示结束")
+```
+
+## client.py
+```python
+# -*- coding: utf-8 -*-
+print("加密通道客户端演示开始")
+import random
+from Crypto.PublicKey import RSA
+from Crypto.Cipher import PKCS1_v1_5
+from Crypto.Cipher import AES  
+import base64
+import hashlib
+import json
+import time
+
+public_key = """-----BEGIN PUBLIC KEY-----
+MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDfEQ82qUrto7h4BL3TsA/DFXSd
+M44cbeY4kPccD7gLGhaZRClzYKIh5zYdfjBGF+0HXfMa1u9b7GNs2AjVIsx8Kx0Q
+LnMfmtkmGWGhOXz/9IDLKJOx0weKv61gysKItgzVKn2mbLool4R/PQBc3AjDyHw+
+io1KpVz+3kRTaGs1fQIDAQAB
+-----END PUBLIC KEY-----
+"""
+
+# 公钥加密
+def rsa_encode(message, public_key):
+    rsakey = RSA.importKey(public_key)  # 导入读取到的公钥
+    cipher = PKCS1_v1_5.new(rsakey)  # 生成对象
+    # 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
+    cipher_text = base64.b64encode(cipher.encrypt(message.encode(encoding="utf-8")))
+    # 公钥每次加密的结果不一样跟对数据的padding（填充）有关
+    return cipher_text.decode()
+
+class PrpCrypt(object):
+ 
+    def __init__(self, key):
+        self.key = key.encode('utf-8')
+        self.mode = AES.MODE_CBC
+ 
+    # 加密函数，如果text不足16位就用空格补足为16位，
+    # 如果大于16当时不是16的倍数，那就补足为16的倍数。
+    def encrypt(self, text):
+        text = text.encode('utf-8')
+        cryptor = AES.new(self.key, self.mode, b'0000000000000000')
+        # 这里密钥key 长度必须为16（AES-128）,
+        # 24（AES-192）,或者32 （AES-256）Bytes 长度
+        # 目前AES-128 足够目前使用
+        length = 16
+        count = len(text)
+        if count < length:
+            add = (length - count)
+            # \0 backspace
+            # text = text + ('\0' * add)
+            text = text + ('\0' * add).encode('utf-8')
+        elif count > length:
+            add = (length - (count % length))
+            # text = text + ('\0' * add)
+            text = text + ('\0' * add).encode('utf-8')
+        self.ciphertext = cryptor.encrypt(text)
+        # 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
+        # 所以这里统一把加密后的字符串转化为16进制字符串
+        return base64.b64encode(self.ciphertext)
+        
+        # 解密后，去掉补足的空格用strip() 去掉
+    def decrypt(self, text):
+        cryptor = AES.new(self.key, self.mode, b'0000000000000000')
+        plain_text = cryptor.decrypt(base64.b64decode(text))
+        # return plain_text.rstrip('\0')
+        return bytes.decode(plain_text).rstrip('\0')
+
+#初始化阶段
+while True:
+    try:
+        pipe = open("pipe.txt", mode='r')
+    except:
+        time.sleep(1)
+    else:
+        break
+pipe.close()
+#协商密钥
+key = str(random.randint(1000000000000000,9999999999999999))
+akey = PrpCrypt(key)
+cipher = rsa_encode(key, public_key)
+data = json.dumps({"key":cipher})
+file = open('pipe.txt','w')
+print(data,file = file)
+file.close()
+while True:
+    pipe = open("pipe.txt", mode='r')
+    if pipe.read() == "\n":
+        pipe.close()
+        break
+    pipe.close()
+    time.sleep(1)
+print("成功发送密钥",key)
+print("已建立连接")
+
+#处理阶段
+#Single Quest
+name = input("请输入用户名：")
+pwd = input("请输入密码：")
+hash = hashlib.md5(pwd.encode(encoding='UTF-8')).hexdigest()
+data = json.dumps({"from":"Client","data":akey.encrypt(json.dumps({"name":name,"pwd":hash})).decode("utf-8")})
+file = open('pipe.txt','w')
+print(data,file = file)
+file.close()
+print("已发出，等待回应")
+while True:
+    pipe = open("pipe.txt", mode='r')
+    data = pipe.read()
+    if not data == "\n":
+        data = json.loads(data)
+        if data["from"] == "Server":
+            pipe.close()
+            break
+    pipe.close()
+    time.sleep(1)
+print("已收到回应")
+data = akey.decrypt(data["data"])
+print(data)
+print("加密通道客户端演示结束")
+```
+
+# 后记
+  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🤪。