密码学加密解密经典算法Python实现课程设计Python.rar

# -*- coding: utf-8 -*- from DES_destruct import * import re import base64 def write_in_file(str_mess): try: f = open('DES.txt','w',encoding='utf-8') f.write(str_mess) f.close() print("文件输出成功！") except IOError: print('文件加解密出错！！！') def read_out_file(): try: f = open('DES.txt','r',encoding = 'utf-8') mess = f.read() f.close() print("文件读取成功！") return mess except IOError: print('文件加解密出错！！！') #字符串转化为二进制 def str2bin(message): res = "" for i in message: tmp = bin(ord(i))[2:] for j in range(0,8-len(tmp)): tmp = '0'+ tmp #把输出的b给去掉 res += tmp return res #二进制转化为字符串 def bin2str(bin_str): res = "" tmp = re.findall(r'.{8}',bin_str) for i in tmp: res += chr(int(i,2)) return res # print("未经过编码的加密结果:"+res) # print("经过base64编码:"+str(base64.b64encode(res.encode('utf-8')),'utf-8')) #IP盒处理 def ip_change(bin_str): res = "" for i in IP_table: res += bin_str[i-1] #数组下标i-1 return res #IP逆盒处理 def ip_re_change(bin_str): res = "" for i in IP_re_table: res += bin_str[i-1] return res #E盒置换 def e_key(bin_str): res = "" for i in E: res += bin_str[i-1] return res #字符串异或操作 def str_xor(my_str1,my_str2): res = "" for i in range(0,len(my_str1)): xor_res = int(my_str1[i],10)^int(my_str2[i],10) #变成10进制是转化成字符串 2进制与10进制异或结果一样，都是1,0 if xor_res == 1: res += '1' if xor_res == 0: res += '0' return res #循环左移操作 def left_turn(my_str,num): left_res = my_str[num:len(my_str)] left_res = my_str[0:num]+left_res return left_res #秘钥的PC-1置换 def change_key1(my_key): res = "" for i in PC_1: res += my_key[i-1] return res #秘钥的PC-2置换 def change_key2(my_key): res = "" for i in PC_2: res += my_key[i-1] return res # S盒过程 def s_box(my_str): res = "" c = 0 for i in range(0,len(my_str),6): now_str = my_str[i:i+6] row = int(now_str[0]+now_str[5],2) col = int(now_str[1:5],2) num = bin(S[c][row*16 + col])[2:] #利用了bin输出有可能不是4位str类型的值，所以才有下面的循环并且加上字符0 for gz in range(0,4-len(num)): num = '0'+ num res += num c += 1 return res #P盒置换 def p_box(bin_str): res = "" for i in P: res += bin_str[i-1] return res # F函数的实现 def fun_f(bin_str,key): first_output = e_key(bin_str) second_output = str_xor(first_output,key) third_output = s_box(second_output) last_output = p_box(third_output) return last_output def gen_key(key): key_list = [] divide_output = change_key1(key) key_C0 = divide_output[0:28] key_D0 = divide_output[28:] for i in SHIFT: key_c = left_turn(key_C0,i) key_d = left_turn(key_D0,i) key_output = change_key2(key_c + key_d) key_list.append(key_output) return key_list def des_encrypt_one(bin_message,bin_key): #64位二进制加密的测试 #bin_message = deal_mess(str2bin(message)) mes_ip_bin = ip_change(bin_message) #bin_key = input_key_judge(str2bin(key)) key_lst = gen_key(bin_key) mes_left = mes_ip_bin[0:32] mes_right = mes_ip_bin[32:] for i in range(0,15): mes_tmp = mes_right f_result = fun_f(mes_tmp,key_lst[i]) mes_right = str_xor(f_result,mes_left) mes_left = mes_tmp f_result = fun_f(mes_right,key_lst[15]) mes_fin_left = str_xor(mes_left,f_result) mes_fin_right = mes_right fin_message = ip_re_change(mes_fin_left + mes_fin_right) return fin_message ##64位二进制解密的测试,注意秘钥反过来了，不要写错了 def des_decrypt_one(bin_mess,bin_key): mes_ip_bin = ip_change(bin_mess) #bin_key = input_key_judge(str2bin(key)) key_lst = gen_key(bin_key) lst = range(1,16) cipher_left = mes_ip_bin[0:32] cipher_right = mes_ip_bin[32:] for i in lst[::-1]: mes_tmp = cipher_right cipher_right = str_xor(cipher_left,fun_f(cipher_right,key_lst[i])) cipher_left = mes_tmp fin_left = str_xor(cipher_left,fun_f(cipher_right,key_lst[0])) fin_right = cipher_right fin_output = fin_left + fin_right bin_plain = ip_re_change(fin_output) res = bin2str(bin_plain) return res #简单判断以及处理信息分组 def deal_mess(bin_mess): """ :param bin_mess: 二进制的信息流 :return: 补充的64位信息流 """ ans = len(bin_mess) if ans % 64 != 0: for i in range( 64 - (ans%64)): #不够64位补充0 bin_mess += '0' return bin_mess #查看秘钥是否为64位 def input_key_judge(bin_key): """ 全部秘钥以补0的方式实现长度不满足64位的 :param bin_key: """ ans = len(bin_key) if len(bin_key) < 64: if ans % 64 != 0: for i in range(64 - (ans % 64)): # 不够64位补充0 bin_key += '0' # else: # bin_key = bin_key[0:64] #秘钥超过64位的情况默认就是应该跟密文一样长 直接将密钥变为跟明文一样的长度，虽然安全性会有所下降 return bin_key def all_message_encrypt(message,key): bin_mess = deal_mess(str2bin(message)) res = "" bin_key = input_key_judge(str2bin(key)) tmp = re.findall(r'.{64}',bin_mess) for i in tmp: res += des_encrypt_one(i,bin_key) return res def all_message_decrypt(message,key): bin_mess = deal_mess(str2bin(message)) res = "" bin_key = input_key_judge(str2bin(key)) tmp = re.findall(r'.{64}',bin_mess) for i in tmp: res += des_decrypt_one(i,bin_key) return res def get_mode(): print("1.加密") print("2.解密") mode = input() if mode == '1': print("请输入信息输入字符串不能为空：") message = input().replace(' ','') print("请输入你的秘钥：") key = input().replace(' ','') s = all_message_encrypt(message,key) out_mess = bin2str(s) print("加密过后的内容:"+ out_mess) write_in_file(out_mess) #print(type(out_mess)) # base_out_mess = base64.b64encode(out_mess.encode('utf-8')) # print("Base64编码过后:"+ base_out_mess.decode()) elif mode == '2': # print("请输入信息输入字符串不能为空：") # message = input().replace(' ', '') print("请输入你的秘钥：") key = input().replace(' ', '') message = read_out_file() s = all_message_decrypt(message, key) #out_mess = bin2str(s) print("解密后的信息："+ s) else: print("请重新输入！") if __name__ == '__main__': while True: get_mode()