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【题目】
1） 实现MD5 Hash函数算法，具体要求：
A. 实现MD5算法的消息压缩过程，任选一个大小为10M的word文档，并计算其Hash值（注意，计算的是包括文件头等在内的完整文件的Hash函数值，而不仅仅是文件内容的Hash函数值）；
【实现代码】
#!/usr/bin/env python# -*- coding: utf-8 -*-"""Created on Wed Jan 3 19:32:17 2018@author: HP"""from time import clock#初始变量 小端字节序：书上A = 0x01234567 这是内存中的顺序，并不是说A的值为0x01234567#在程序中应该把A赋值为0x67452301A = '0x67452301' B = '0xefcdab89' C = '0x98badcfe' D = '0x10325476' #步函数F = lambda x,y,z:((x&y)|((~x)&z)) G = lambda x,y,z:((x&z)|(y&(~z))) H = lambda x,y,z:(x^y^z) I = lambda x,y,z:(y^(x|(~z))) #循环左移函数（x循环左移n位）L = lambda x,n:(((x< >(32-n)))&(0xffffffff)) #每轮16步循环左移的位数s1 = (7,12,17,22)*4 s2 = (5,9,14,20)*4 s3 = (4,11,16,23)*4 s4 = (6,10,15,21)*4 #每轮16步M子组的排序m_1 = (0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15) m_2 = (1,6,11,0,5,10,15,4,9,14,3,8,13,2,7,12) m_3 = (5,8,11,14,1,4,7,10,13,0,3,6,9,12,15,2) m_4 = (0,7,14,5,12,3,10,1,8,15,6,13,4,11,2,9) #4轮64步的T表T = ['0xd76aa478', '0xe8c7b756', '0x242070db', '0xc1bdceee', '0xf57c0faf', '0x4787c62a', '0xa8304613', '0xfd469501', '0x698098d8', '0x8b44f7af', '0xffff5bb1', '0x895cd7be', '0x6b901122', '0xfd987193', '0xa679438e', '0x49b40821', '0xf61e2562', '0xc040b340', '0x265e5a51', '0xe9b6c7aa', '0xd62f105d', '0x02441453', '0xd8a1e681', '0xe7d3fbc8', '0x21e1cde6', '0xc33707d6', '0xf4d50d87', '0x455a14ed', '0xa9e3e905', '0xfcefa3f8', '0x676f02d9', '0x8d2a4c8a', '0xfffa3942', '0x8771f681', '0x6d9d6122', '0xfde5380c', '0xa4beea44', '0x4bdecfa9', '0xf6bb4b60', '0xbebfbc70', '0x289b7ec6', '0xeaa127fa', '0xd4ef3085', '0x04881d05', '0xd9d4d039', '0xe6db99e5', '0x1fa27cf8', '0xc4ac5665', '0xf4292244', '0x432aff97', '0xab9423a7', '0xfc93a039', '0x655b59c3', '0x8f0ccc92', '0xffeff47d', '0x85845dd1', '0x6fa87e4f', '0xfe2ce6e0', '0xa3014314', '0x4e0811a1', '0xf7537e82', '0xbd3af235', '0x2ad7d2bb', '0xeb86d391'] #翻转十六进制数的顺序：'0x01234567' => '0x67452301' def reverse_hex(hex_str): hex_str = hex_str[2:] hex_str_list = [] for i in range(0,len(hex_str),2): hex_str_list.append(hex_str[i:i+2]) hex_str_list.reverse() hex_str_result = '0x' + ''.join(hex_str_list) return hex_str_result #md5类class MD5(object): def __init__(self, plaintext): self.plist = ["0x"+hex(x)[2:].rjust(2, '0') for x in plaintext] self.plength = len(self.plist)*8 print(self.plength) self.__fill() def __fill(self): #先填充一个10000000 self.plist.append('0x80') #然后填充00000000直到剩下64位也就是8字节 while (len(self.plist)+8)%64 != 0: self.plist.append('0x00') #用消息长度（位）填满最后8字节 #举例长度为8， 我们填充的应该是倒置的0x0800000000000000 #只有这样在内存中的顺序才是0x000000000000000008， 而不是直接填充0x000000000000000008 hex_len = hex(self.plength)[2:] hex_len = '0x' + hex_len.rjust(16, '0') hex_len = reverse_hex(hex_len)[2:] for i in range(0, len(hex_len), 2): self.plist.append('0x' + hex_len[i:i+2]) print(self.plist) #生成每轮的16个M子分组 def genM16(self, order, z): #起始坐标 start = 64*z result = [] for i in range(start, start+64, 4): result.append("0x" + "".join((self.plist[i] + self.plist[i+1] + self.plist[i+2] + self.plist[i+3]).split('0x')[1:])) result = list(map(lambda x: result[x], order)) return list(map(reverse_hex, result)) #对每轮的16步进行加密 def fun(self, fun_list, sfunc, m, s, n): for i in range(16): #模2^32次方加 xx = int(fun_list[0], 16) + sfunc(int(fun_list[1], 16), int(fun_list[2], 16), int(fun_list[3], 16)) + int(m[i], 16) + int(T[16*n+i], 16) xx = xx&0xffffffff #循环左移s[i]位 xx = L(xx, s[i]) #加B xx = (xx + int(fun_list[1], 16))&0xffffffff fun_list[0] = hex(xx) #列表右移一位 x = fun_list.pop() fun_list.insert(0, x) print(fun_list) return fun_list def encrypt(self): abcd_list = [A, B, C, D] for i in range(0, len(self.plist)//64): #把寄存器初始值存下来 AA, BB, CC, DD = abcd_list #生成该组明文四轮的M列表 m_list1 = self.genM16(m_1, i) m_list2 = self.genM16(m_2, i) m_list3 = self.genM16(m_3, i) m_list4 = self.genM16(m_4, i) #进行4轮加密 abcd_list = self.fun(abcd_list, F, m_list1, s1, 0) print("------------------------------------------") abcd_list = self.fun(abcd_list, G, m_list2, s2, 1) print("------------------------------------------") abcd_list = self.fun(abcd_list, H, m_list3, s3, 2) print("------------------------------------------") abcd_list = self.fun(abcd_list, I, m_list4, s4, 3) print("------------------------------------------") #和初始值相加得到该组明文加密结果 output_a = hex((int(AA, 16) + int(abcd_list[0], 16))&0xffffffff) output_b = hex((int(BB, 16) + int(abcd_list[1], 16))&0xffffffff) output_c = hex((int(CC, 16) + int(abcd_list[2], 16))&0xffffffff) output_d = hex((int(DD, 16) + int(abcd_list[3], 16))&0xffffffff) abcd_list = [output_a, output_b, output_c, output_d] print(abcd_list) return abcd_list #将加密函数得到的结果进行反转合并显示出来 def show_result(self, abcd_list): result = "" for x in abcd_list: result += reverse_hex(x)[2:] return result if __name__=="__main__": print("__________开始md5加密______________") #计时 #读文件 fname = input("please enter filename: ") start = clock() f = open(fname, 'rb') plaintext = f.read() f.close() #加密 md5 = MD5(plaintext) ciphertext = md5.show_result(md5.encrypt()) #将密文写入文件 f = open(fname, 'w') f.write(ciphertext) f.close() print("__________加密结束______________") print("密文：%s" %ciphertext) print("加密时长是：%.2f" %(clock()-start)) #print(md5.show_result(md5.encrypt()))
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