import binascii import sys import os.path SV = [0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee, 0xf57c0faf, 0x4787c62a, 0xa8304613, 0xfd469501, 0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be, 0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821, 0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa, 0xd62f105d, 0x2441453, 0xd8a1e681, 0xe7d3fbc8, 0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed, 0xa9e3e905, 0xfcefa3f8, 0x676f02d9, 0x8d2a4c8a, 0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c, 0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70, 0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x4881d05, 0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665, 0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039, 0x655b59c3, 0x8f0ccc92, 0xffeff47d, 0x85845dd1, 0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1, 0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391] # 根据ascil编码把字符转成对应的二进制 def binvalue(val, bitsize): binval = bin(val)[2:] if isinstance(val, int) else bin(ord(val))[2:] if len(binval) > bitsize: raise ("binary value larger than the expected size") while len(binval) < bitsize: binval = "0" + binval return binval def string_to_bit_array(text): array = list() for char in text: binval = binvalue(char, 8) array.extend([int(x) for x in list(binval)]) return array # 循环左移 def leftCircularShift(k, bits): bits = bits % 32 k = k % (2 ** 32) upper = (k << bits) % (2 ** 32) result = upper | (k >> (32 - (bits))) return (result) # 分块 def blockDivide(block, chunks): result = [] size = len(block) // chunks for i in range(0, chunks): result.append(int.from_bytes(block[i * size:(i + 1) * size], byteorder="little")) return result # F函数作用于“比特位”上 # if x then y else z def F(X, Y, Z): compute = ((X & Y) | ((~X) & Z)) return compute # if z then x else y def G(X, Y, Z): return ((X & Z) | (Y & (~Z))) # if X = Y then Z else ~Z def H(X, Y, Z): return (X ^ Y ^ Z) def I(X, Y, Z): return (Y ^ (X | (~Z))) # 四个F函数 def FF(a, b, c, d, M, s, t): result = b + leftCircularShift((a + F(b, c, d) + M + t), s) return (result) def GG(a, b, c, d, M, s, t): result = b + leftCircularShift((a + G(b, c, d) + M + t), s) return (result) def HH(a, b, c, d, M, s, t): result = b + leftCircularShift((a + H(b, c, d) + M + t), s) return (result) def II(a, b, c, d, M, s, t): result = b + leftCircularShift((a + I(b, c, d) + M + t), s) return (result) # 数据转换 def fmt8(num): bighex = "{0:08x}".format(num) binver = binascii.unhexlify(bighex) result = "{0:08x}".format(int.from_bytes(binver, byteorder='little')) return (result) # 计算比特长度 def bitlen(bitstring): return len(bitstring) * 8 def md5sum(msg): # 计算比特长度，如果内容过长，64个比特放不下。就取低64bit。 msgLen = bitlen(msg) % (2 ** 64) # 先填充一个0x80，其实是先填充一个1，后面跟对应个数的0，因为一个明文的编码至少需要8比特，所以直接填充 0b10000000即0x80 msg = msg + b'\x80' # 0x80 = 1000 0000 # 似乎各种编码，即使是一个字母，都至少得1个字节，即8bit才能表示，所以不会出现原文55bit，pad1就满足的情况？可是不对呀，要是二进制文件呢？ # 填充0到满足要求为止。 zeroPad = (448 - (msgLen + 8) % 512) % 512 zeroPad //= 8 msg = msg + b'\x00' * zeroPad + msgLen.to_bytes(8, byteorder='little') # 计算循环轮数，512个为一轮 msgLen = bitlen(msg) iterations = msgLen // 512 # 初始化变量 # 算法魔改的第一个点，也是最明显的点 # A = 0x67452301 # B = 0xefcdab89 # C = 0x98badcfe # D = 0x10325476 # 魔改版 A = 0x67552301 B = 0xEDCDAB89 C = 0x98BADEFE D = 0x16325476 # MD5的主体就是对abcd进行n次的迭代，所以得有个初始值，可以随便选，也可以用默认的魔数，这个改起来毫无风险，所以大家爱魔改它，甚至改这个都不算魔改。 # main loop for i in range(0, iterations): a = A b = B c = C d = D block = msg[i * 64:(i + 1) * 64] # 明文的处理，顺便调整了一下端序 M = blockDivide(block, 16) # Rounds a = FF(a, b, c, d, M[0], 7, SV[0]) d = FF(d, a, b, c, M[1], 12, SV[1]) c = FF(c, d, a, b, M[2], 17, SV[2]) b = FF(b, c, d, a, M[3], 22, SV[3]) a = FF(a, b, c, d, M[4], 7, SV[4]) d = FF(d, a, b, c, M[5], 12, SV[5]) c = FF(c, d, a, b, M[6], 17, SV[6]) b = FF(b, c, d, a, M[7], 22, SV[7]) a = FF(a, b, c, d, M[8], 7, SV[8]) d = FF(d, a, b, c, M[9], 12, SV[9]) c = FF(c, d, a, b, M[10], 17, SV[10]) b = FF(b, c, d, a, M[11], 22, SV[11]) a = FF(a, b, c, d, M[12], 7, SV[12]) d = FF(d, a, b, c, M[13], 12, SV[13]) c = FF(c, d, a, b, M[14], 17, SV[14]) b = FF(b, c, d, a, M[15], 22, SV[15]) a = GG(a, b, c, d, M[1], 5, SV[16]) d = GG(d, a, b, c, M[6], 9, SV[17]) c = GG(c, d, a, b, M[11], 14, SV[18]) b = GG(b, c, d, a, M[0], 20, SV[19]) a = GG(a, b, c, d, M[5], 5, SV[20]) d = GG(d, a, b, c, M[10], 9, SV[21]) c = GG(c, d, a, b, M[15], 14, SV[22]) b = GG(b, c, d, a, M[4], 20, SV[23]) a = GG(a, b, c, d, M[9], 5, SV[24]) d = GG(d, a, b, c, M[14], 9, SV[25]) c = GG(c, d, a, b, M[3], 14, SV[26]) b = GG(b, c, d, a, M[8], 20, SV[27]) a = GG(a, b, c, d, M[13], 5, SV[28]) d = GG(d, a, b, c, M[2], 9, SV[29]) c = GG(c, d, a, b, M[7], 14, SV[30]) b = GG(b, c, d, a, M[12], 20, SV[31]) a = HH(a, b, c, d, M[5], 4, SV[32]) d = HH(d, a, b, c, M[8], 11, SV[33]) c = HH(c, d, a, b, M[11], 16, SV[34]) b = HH(b, c, d, a, M[14], 23, SV[35]) a = HH(a, b, c, d, M[1], 4, SV[36]) d = HH(d, a, b, c, M[4], 11, SV[37]) c = HH(c, d, a, b, M[7], 16, SV[38]) b = HH(b, c, d, a, M[10], 23, SV[39]) a = HH(a, b, c, d, M[13], 4, SV[40]) d = HH(d, a, b, c, M[0], 11, SV[41]) c = HH(c, d, a, b, M[3], 16, SV[42]) b = HH(b, c, d, a, M[6], 23, SV[43]) a = HH(a, b, c, d, M[9], 4, SV[44]) d = HH(d, a, b, c, M[12], 11, SV[45]) c = HH(c, d, a, b, M[15], 16, SV[46]) b = HH(b, c, d, a, M[2], 23, SV[47]) a = II(a, b, c, d, M[0], 6, SV[48]) d = II(d, a, b, c, M[7], 10, SV[49]) c = II(c, d, a, b, M[14], 15, SV[50]) b = II(b, c, d, a, M[5], 21, SV[51]) a = II(a, b, c, d, M[12], 6, SV[52]) d = II(d, a, b, c, M[3], 10, SV[53]) c = II(c, d, a, b, M[10], 15, SV[54]) b = II(b, c, d, a, M[1], 21, SV[55]) a = II(a, b, c, d, M[8], 6, SV[56]) d = II(d, a, b, c, M[15], 10, SV[57]) c = II(c, d, a, b, M[6], 15, SV[58]) b = II(b, c, d, a, M[13], 21, SV[59]) a = II(a, b, c, d, M[4], 6, SV[60]) d = II(d, a, b, c, M[11], 10, SV[61]) c = II(c, d, a, b, M[2], 15, SV[62]) b = II(b, c, d, a, M[9], 21, SV[63]) A = (A + a) % (2 ** 32) B = (B + b) % (2 ** 32) C = (C + c) % (2 ** 32) D = (D + d) % (2 ** 32) result = fmt8(A) + fmt8(B) + fmt8(C) + fmt8(D) return result if __name__ == "__main__": data = str("123456").encode("UTF-8") print("plainText: ", data) print("result: ", md5sum(data))