#!/usr/bin/env python
# -*- encoding:utf-8 -*-
"""
基于官方版本修改为同时支持 python2、python3 并整理入一个文件内。
部分参考自 https://github.com/chenjianjx/wechat-encrypt-python3
"""
import xml.etree.cElementTree as ET
import base64
import string
import random
import hashlib
import time
import struct
import socket
import sys
PY2 = False
if sys.version_info[0] == 2:
PY2 = True
try:
from Crypto.Cipher import AES
except ImportError:
print ('please install Crypto at first: $ pip install pycrypto')
Crypt_OK = 0
Crypt_ValidateSignature_Error = -40001
Crypt_ParseXml_Error = -40002
Crypt_ComputeSignature_Error = -40003
Crypt_IllegalAesKey = -40004
Crypt_ValidateAppid_Error = -40005
Crypt_EncryptAES_Error = -40006
Crypt_DecryptAES_Error = -40007
Crypt_IllegalBuffer = -40008
Crypt_EncodeBase64_Error = -40009
Crypt_DecodeBase64_Error = -40010
Crypt_GenReturnXml_Error = -40011
def getSHA1(token, timestamp, nonce, encrypt):
"""用SHA1算法生成安全签名
@param token: 票据
@param timestamp: 时间戳
@param encrypt: 密文
@param nonce: 随机字符串
@return: 安全签名
"""
try:
sortlist = [token, timestamp, nonce, encrypt]
sortlist.sort()
sha = hashlib.sha1()
sha.update("".join(sortlist).encode('utf-8'))
return Crypt_OK, sha.hexdigest()
except Exception:
return Crypt_ComputeSignature_Error, None
class XMLParse:
"""提供提取消息格式中的密文及生成回复消息格式的接口"""
# xml消息模板
AES_TEXT_RESPONSE_TEMPLATE = """<xml>
<Encrypt><![CDATA[%(msg_encrypt)s]]></Encrypt>
<MsgSignature><![CDATA[%(msg_signaturet)s]]></MsgSignature>
<TimeStamp>%(timestamp)s</TimeStamp>
<Nonce><![CDATA[%(nonce)s]]></Nonce>
</xml>"""
def extract(self, xmltext):
"""提取出xml数据包中的加密消息
@param xmltext: 待提取的xml字符串
@return: 提取出的加密消息字符串
"""
try:
xml_tree = ET.fromstring(xmltext)
encrypt = xml_tree.find("Encrypt")
touser_name = xml_tree.find("ToUserName")
return Crypt_OK, encrypt.text, touser_name.text
except Exception:
return Crypt_ParseXml_Error, None, None
def generate(self, encrypt, signature, timestamp, nonce):
"""生成xml消息
@param encrypt: 加密后的消息密文
@param signature: 安全签名
@param timestamp: 时间戳
@param nonce: 随机字符串
@return: 生成的xml字符串
"""
resp_dict = {
'msg_encrypt': encrypt,
'msg_signaturet': signature,
'timestamp': timestamp,
'nonce': nonce,
}
resp_xml = self.AES_TEXT_RESPONSE_TEMPLATE % resp_dict
return resp_xml
class PKCS7Encoder():
"""提供基于PKCS7算法的加解密接口"""
block_size = 32
def encode(self, text):
""" 对需要加密的明文进行填充补位
@param text: 需要进行填充补位操作的明文
@return: 补齐明文字符串
"""
text_length = len(text)
# 计算需要填充的位数
amount_to_pad = self.block_size - (text_length % self.block_size)
if amount_to_pad == 0:
amount_to_pad = self.block_size
# 获得补位所用的字符
if PY2:
pad = chr(amount_to_pad)
else:
pad = bytearray([amount_to_pad])
return text + pad * amount_to_pad
def decode(self, decrypted):
"""删除解密后明文的补位字符
@param decrypted: 解密后的明文
@return: 删除补位字符后的明文
"""
pad = ord(decrypted[-1])
if pad < 1 or pad > 32:
pad = 0
return decrypted[:-pad]
class Prpcrypt(object):
"""提供接收和推送给公众平台消息的加解密接口"""
def __init__(self, key, appid):
# self.key = base64.b64decode(key+"=")
self.key = key
# 设置加解密模式为AES的CBC模式
self.mode = AES.MODE_CBC
self.appid = appid
def encrypt(self, xml):
"""对明文进行加密
@param text: 需要加密的明文
@return: 加密得到的字符串
"""
# 16位随机字符串添加到明文开头
xml = xml.encode('utf-8')
if PY2:
text = self.get_random_str() +\
struct.pack("I", socket.htonl(len(xml))) + xml + self.appid
else:
text = self.get_random_str().encode('utf-8') +\
struct.pack("I", socket.htonl(len(xml))) +\
xml + self.appid.encode('utf-8')
# 使用自定义的填充方式对明文进行补位填充
pkcs7 = PKCS7Encoder()
text = pkcs7.encode(text)
# 加密
cryptor = AES.new(self.key, self.mode, self.key[:16])
try:
ciphertext = cryptor.encrypt(text)
# 使用BASE64对加密后的字符串进行编码
result = base64.b64encode(ciphertext).decode("utf8")
return Crypt_OK, result
except Exception:
return Crypt_EncryptAES_Error, None
def decrypt(self, text):
"""对解密后的明文进行补位删除
@param text: 密文
@return: 删除填充补位后的明文
"""
try:
cryptor = AES.new(self.key, self.mode, self.key[:16])
# 使用BASE64对密文进行解码，然后AES-CBC解密
plain_text = cryptor.decrypt(base64.b64decode(text))
except Exception:
# print e
return Crypt_DecryptAES_Error, None
try:
if PY2:
pad = ord(plain_text[-1])
else:
pad = plain_text[-1]
# 去掉补位字符串
# pkcs7 = PKCS7Encoder()
# plain_text = pkcs7.encode(plain_text)
# 去除16位随机字符串
content = plain_text[16:-pad]
xml_len = socket.ntohl(struct.unpack("I", content[: 4])[0])
xml_content = content[4: xml_len + 4]
from_appid = content[xml_len + 4:].decode("utf8")
except Exception:
return Crypt_IllegalBuffer, None
if from_appid != self.appid:
return Crypt_ValidateAppid_Error, None
return 0, xml_content
def get_random_str(self):
""" 随机生成16位字符串
@return: 16位字符串
"""
if PY2:
rule = string.letters + string.digits
else:
rule = string.ascii_letters + string.digits
return "".join(random.sample(rule, 16))
class WXBizMsgCrypt(object):
# 构造函数
# @param sToken: 公众平台上，开发者设置的Token
# @param sEncodingAESKey: 公众平台上，开发者设置的EncodingAESKey
# @param sAppId: 企业号的AppId
def __init__(self, sToken, sEncodingAESKey, sAppId):
try:
key = base64.b64decode(sEncodingAESKey + "=")
assert len(key) == 32
except:
AssertionError("[error]: EncodingAESKey unvalid !")
self.token = sToken
self.pc = Prpcrypt(key, sAppId)
def EncryptMsg(self, sReplyMsg, sNonce, timestamp=None):
# 将公众号回复用户的消息加密打包
# @param sReplyMsg: 企业号待回复用户的消息，xml格式的字符串
# @param sTimeStamp: 时间戳，可以自己生成，也可以用URL参数的timestamp,如为None则自动用当前时间
# @param sNonce: 随机串，可以自己生成，也可以用URL参数的nonce
# sEncryptMsg: 加密后的可以直接回复用户的密文，
# 包括msg_signature, timestamp, nonce, encrypt的xml格式的字符串
# return：成功0，sEncryptMsg,失败返回对应的错误码None
ret, encrypt = self.pc.encrypt(sReplyMsg)
if ret != 0:
return ret, None
if timestamp is None:
timestamp = str(int(time.time()))
# 生成安全签名
ret, signature = getSHA1(self.token, timestamp, sNonce, encrypt)
if ret != 0:
return ret, None
xmlParse = XMLParse()
return ret, xmlParse.generate(encrypt, signature, timestamp, sNonce)
def DecryptMsg(self, sPostData, sMsgSignature, sTimeStamp, sNonce):
# 检验消息的真实性，并且获取解密后的明文
# @param sMsgSignature: 签名串，对应URL参数的msg_signature
# @param sTimeStamp: 时间戳，对应URL参数的timestamp
# @param sNonce: 随机串，对应URL参数的nonce
# @param sPostData: 密文，对应POST请求的数据
# xml_content: 解密后的原文，当return返回0时有效
# @return: 成功0，失败返回对应的错误码
# 验证安全签名
xmlParse = XMLParse()
ret, encrypt, touser_name = xmlParse.extract(sPostData)
if ret != 0:
return ret, None
ret, signature = getSHA1(self.token, sTimeStamp, sNonce, encrypt)
if ret != 0:
return ret, None
if not signature == sMsgSignature:
return Crypt_ValidateSignature_Error, None
ret, xml_content = self.pc.decrypt(encrypt)
if not PY2:
xml_content = xml_content.decode('utf-8')
return ret, xml_content
