MD5加密--Python实现_python md5

1、简介

MD5消息摘要算法（MD5 Message-Digest Algorithm），一种被广泛使用的密码散列函数，可以产生出一个128位（16字节）的散列值（hash value），用于确保信息传输完整一致。

2、特点

MD5是最常见的摘要算法，速度很快，生成结果是固定的128 bit 字节，通常用一个32位的16进制字符串表示。

MD5加密算法属于单向加密算法。MD5算法对比普通的加密算法缺少了解密的过程，它无法从密文（散列值）反过来得到原文。

单向加密算法是中在加密过程中不适应秘钥，将数据加密处理成加密数据，加密数据无法被解密。因为无法通过加密数据反向得到原来的内容，单向加密算法又被称为不可逆加密算法。单向加密算法一般使用哈希算法来生成密文，又称为哈希加密算法。

3、Python实现

# -*- codeding = uft-8 -*-
 
def int2bin(n, count=24):
    return "".join([str((n >> y) & 1) for y in range(count-1, -1, -1)])
 
class MD5(object):
    # 初始化密文
    def __init__(self, message):
        self.message = message
        self.ciphertext = ""
 
        self.A = 0x67452301
        self.B = 0xEFCDAB89
        self.C = 0x98BADCFE
        self.D = 0x10325476
        self.init_A = 0x67452301
        self.init_B = 0xEFCDAB89
        self.init_C = 0x98BADCFE
        self.init_D = 0x10325476
        '''
        self.A = 0x01234567
        self.B = 0x89ABCDEF
        self.C = 0xFEDCBA98
        self.D = 0x76543210
         '''
        #设置常数表T
        self.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]
        #循环左移位数
        self.s = [7,12,17,22,7,12,17,22,7,12,17,22,7,12,17,22,
                    5,9,14,20,5,9,14,20,5,9,14,20,5,9,14,20,
                    4,11,16,23,4,11,16,23,4,11,16,23,4,11,16,23,
                    6,10,15,21,6,10,15,21,6,10,15,21,6,10,15,21]
        self.m = [0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,
                    1,6,11,0,5,10,15,4,9,14,3,8,13,2,7,12,
                    5,8,11,14,1,4,7,10,13,0,3,6,9,12,15,2,
                    0,7,14,5,12,3,10,1,8,15,6,13,4,11,2,9]
 
 
 
    # 附加填充位
    def fill_text(self):
        for i in range(len(self.message)):
            c = int2bin(ord(self.message[i]), 8)
            self.ciphertext += c
 
        if (len(self.ciphertext)%512 != 448):
            if ((len(self.ciphertext)+1)%512 != 448):
                self.ciphertext += '1'
            while (len(self.ciphertext)%512 != 448):
                self.ciphertext += '0'
 
        length = len(self.message)*8
        if (length <= 255):
            length = int2bin(length, 8)
        else:
            length = int2bin(length, 16)
            temp = length[8:12]+length[12:16]+length[0:4]+length[4:8]
            length = temp
 
        self.ciphertext += length
        while (len(self.ciphertext)%512 != 0):
            self.ciphertext += '0'
 
    # 分组处理（迭代压缩）
    def circuit_shift(self, x, amount):
        x &= 0xFFFFFFFF
        return ((x << amount) | (x >> (32 - amount))) & 0xFFFFFFFF
 
    def change_pos(self):
        a = self.A
        b = self.B
        c = self.C
        d = self.D
        self.A = d
        self.B = a
        self.C = b
        self.D = c
 
    def FF(self, mj, s, ti):
        mj = int(mj, 2)
        temp = self.F(self.B, self.C, self.D) + self.A + mj + ti
        temp = self.circuit_shift(temp, s)
        self.A = (self.B + temp)%pow(2, 32)
        self.change_pos()
 
    def GG(self, mj, s, ti):
        mj = int(mj, 2)
        temp = self.G(self.B, self.C, self.D) + self.A + mj + ti
        temp = self.circuit_shift(temp, s)
        self.A = (self.B + temp)%pow(2, 32)
        self.change_pos()
 
    def HH(self, mj, s, ti):
        mj = int(mj, 2)
        temp = self.H(self.B, self.C, self.D) + self.A + mj + ti
        temp = self.circuit_shift(temp, s)
        self.A = (self.B + temp)%pow(2, 32)
        self.change_pos()
 
    def II(self, mj, s, ti):
        mj = int(mj, 2)
        temp = self.I(self.B, self.C, self.D) + self.A + mj + ti
        temp = self.circuit_shift(temp, s)
        self.A = (self.B + temp)%pow(2, 32)
        self.change_pos()
 
 
    def F(self, X, Y, Z):
        return (X & Y) | ((~X) & Z)
    def G(self, X, Y, Z):
        return (X & Z) | (Y & (~Z))
    def H(self, X, Y, Z):
        return X ^ Y ^ Z
    def I(self, X, Y, Z):
        return Y ^ (X | (~Z))
 
    def group_processing(self):
        M = []
        for i in range(0, 512, 32):
            num = ""
            # 获取每一段的标准十六进制形式
            for j in range(0, len(self.ciphertext[i:i+32]), 4):
                temp = self.ciphertext[i:i+32][j:j + 4]
                temp = hex(int(temp, 2))
                num += temp[2]
            # 对十六进制进行小端排序
            num_tmp = ""
            for j in range(8, 0, -2):
                temp = num[j-2:j]
                num_tmp += temp
 
            num = ""
            for i in range(len(num_tmp)):
                num += int2bin(int(num_tmp[i], 16), 4)
            M.append(num)
 
        #print(M)
 
 
 
        for j in range(0, 16, 4):
            self.FF(M[self.m[j]], self.s[j], self.T[j])
            self.FF(M[self.m[j+1]], self.s[j+1], self.T[j+1])
            self.FF(M[self.m[j+2]], self.s[j+2], self.T[j+2])
            self.FF(M[self.m[j+3]], self.s[j+3], self.T[j+3])
 
        for j in range(0, 16, 4):
            self.GG(M[self.m[16+j]], self.s[16+j], self.T[16+j])
            self.GG(M[self.m[16+j+1]], self.s[16+j+1], self.T[16+j+1])
            self.GG(M[self.m[16+j+2]], self.s[16+j+2], self.T[16+j+2])
            self.GG(M[self.m[16+j+3]], self.s[16+j+3], self.T[16+j+3])
 
 
        for j in range(0, 16, 4):
            self.HH(M[self.m[32+j]], self.s[32+j], self.T[32+j])
            self.HH(M[self.m[32+j+1]], self.s[32+j+1], self.T[32+j+1])
            self.HH(M[self.m[32+j+2]], self.s[32+j+2], self.T[32+j+2])
            self.HH(M[self.m[32+j+3]], self.s[32+j+3], self.T[32+j+3])
 
 
        for j in range(0, 16, 4):
            self.II(M[self.m[48+j]], self.s[48+j], self.T[48+j])
            self.II(M[self.m[48+j+1]], self.s[48+j+1], self.T[48+j+1])
            self.II(M[self.m[48+j+2]], self.s[48+j+2], self.T[48+j+2])
            self.II(M[self.m[48+j+3]], self.s[48+j+3], self.T[48+j+3])
 
        self.A = (self.A+self.init_A)%pow(2, 32)
        self.B = (self.B+self.init_B)%pow(2, 32)
        self.C = (self.C+self.init_C)%pow(2, 32)
        self.D = (self.D+self.init_D)%pow(2, 32)
        '''
        print("A:{}".format(hex(self.A)))
        print("B:{}".format(hex(self.B)))
        print("C:{}".format(hex(self.C)))
        print("D:{}".format(hex(self.D)))
        '''
        answer = ""
        for register in [self.A, self.B, self.C, self.D]:
            register = hex(register)[2:]
            for i in range(8, 0, -2):
                answer += str(register[i-2:i])
 
        return answer
 
 
# 测试
# message = input("输入要加密的字符串：")
# MD5 = MD5(message)
# MD5.fill_text()
# result = MD5.group_processing()
# print("32位小写MD5加密：{}".format(result))