# -*- coding: utf-8 -*-
"""
Created on Tue Oct 26 18:29:17 2021
@author: think
"""
from pyDes import des, PAD_PKCS5
from hashlib import md5
import rsa
class digitalEnvelope:
def __init__(self):
pass
#数字信封
def getEnvelope(self, message, privkeyS, pubkeyR, key):
#输入：message：一般字符串，privkeyS：rsa库的private_key类，
#pubkeyR：接收方的公钥，rsa库的private_key类，有点拧巴但必须这么写
#key：一般8位字符串，输出：utf-8字符串
Sign = self.digitalSignature(message, privkeyS)
midMessage = message.encode('utf-8') + Sign
crypto_msg = self.desEncoding(midMessage, key)
crypto_key = self.rsaEncryption(key.encode("utf-8"), pubkeyR)
crypto = crypto_msg + crypto_key
return crypto
def removeEnvelope(self, crypto, pubkeyS, privkeyR):
#获得公钥key
crypto_key = crypto[-64:]#后64位为公钥RSA加密后的结果
crypto_msg = crypto[:-64]
key = self.rsaDecryption(crypto_key, privkeyR)
#获得消息和数字签名
midMessage = self.desDecoding(crypto_msg, key)
Sign = midMessage[-64:]#数字签名也一定是64位
message = midMessage[:-64]
#有效性验证
#md5不该打包到digitalSignature里来着，失策了，但不想改了
m = md5()
m.update(message)
checkHash = m.digest()
msgHash = self.rsaDecryption(Sign, pubkeyS)
if msgHash == checkHash:
print("The message has not been changed.")
else:
print("The message has been changed.")
return message
#消息摘要
def digitalSignature(self, message, privkeyS):#利用Sender的私钥加密
#输入：message：一般字符串，privkeyS：int; 输出：64位utf-8字符串
#先获得摘要
m = md5()
m.update(message.encode('utf-8'))
Hash = m.digest()
#这里获得utf-8字符串
#然后用Sender的私钥加密该摘要
Sign = self.rsaEncryption(Hash, privkeyS)
return Sign
#获得RSA密钥
def generateRSAKeys(self, num = 512):
return rsa.newkeys(num)
#RSA加密解密
#在这里，ke和kd并不一定是公钥或私钥
#默认采用512位RSA加密，即128位16进制数
def rsaEncryption(self, message, ke):
#输入：任意utf-8字符串，输出：64位utf-8字符串
C = rsa.encrypt(message, ke)
return C
def rsaDecryption(self, message, kd):
#输入：64位utf-8字符串，输出：任意utf-8字符串
M = rsa.decrypt(message, kd)
return M
#Des加密解密
def desEncoding(self, message, key):
#输入：message：任意utf-8字符串，key：8位任意字符串; 输出：8的整数倍位数utf-8字符串
d = des(key, padmode = PAD_PKCS5)
C = d.encrypt(message, padmode = PAD_PKCS5)
return C
def desDecoding(self, C, key):
#输入：C：utf-8字符串，key：8位任意字符串; 输出：任意utf-8字符串
d = des(key, padmode = PAD_PKCS5)
M = d.decrypt(C, padmode = PAD_PKCS5)
return M
