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| import math
# Initial Variable A, B, C, D
IV_A = 0x67452301
IV_B = 0xefcdab89
IV_C = 0x98badcfe
IV_D = 0x10325476
# Nonlinear function
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)))
# Loop Left Shift
L = lambda x, n:(((x << n) | (x >> (32 - n))) & (0xffffffff))
# 每次循环左移的位数
Shi = ((7, 12, 17, 22) * 4,
(5, 9, 14, 20) * 4,
(4, 11, 16, 23) * 4,
(6, 10, 15, 21) * 4)
# 每次 M[i]（消息分片）次序。
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))
# 将大端序二进制/十六进制字符串转成小端序
def LittleEndian(s, Hex):
l = len(s)
ans = ""
if Hex == False:
i = l - 8
while i >= 0:
ans += s[i:i + 8]
i -= 8
else:
i = l-2
while i >= 0:
ans += s[i:i + 2]
i -= 2
return ans
# 将字符串转成二进制字符串
def str2Bin(m):
return "".join('{:08b}'.format(ord(x)) for x in m)
# 模2的32次方加
def addMod2_32(a, b):
return (a + b) % (2 ** 32)
# 产生常数T[i]，常数有可能超过32位，需要&0xffffffff操作
# 返回的是十进制的数。
def T(i):
result = (int(4294967296 * abs(math.sin(i)))) & 0xffffffff
return result
def MD5(m):
## str to binstr
m = str2Bin(m)
lm = len(m)
## Padding
lm_mod = lm % 512
### 若原始消息长度刚好满足模512与448同余
### 则还需要填充512位
if lm_mod == 448:
FillLength = 512
elif lm_mod > 448:
FillLength = 512 + 448 - lm_mod
else:
FillLength = 448 - lm_mod
m += '1' + (FillLength - 1) * '0'
# Padding length
length = LittleEndian(bin(lm % (2 ** 64))[2:].zfill(64), False)
m += length
lm = len(m)
## Generate Initial Variable(IV)
A, B, C, D = IV_A, IV_B, IV_C, IV_D
for i in range(0, lm, 512):
Y = m[i:i + 512]
for j in range(4): # 共4轮
for k in range(16): # 每轮16个步骤
# A, B, C, D Backup
AA, BB, CC, DD = A, B, C, D
## Nonlinear function
if j == 0:
t = F(B, C, D)
elif j == 1:
t = G(B, C, D)
elif j == 2:
t = H(B, C, D)
else:
t = I(B, C, D)
T_i = T(16 * j + k + 1)
M_j = LittleEndian(Y[M[j][k] * 32:M[j][k] * 32 + 32], False)
A, C, D = DD, BB, CC
B = addMod2_32(AA, t)
B = addMod2_32(B, int(M_j, 2))
B = addMod2_32(B, T_i)
B = L(B, Shi[j][k])
B = addMod2_32(B, BB)
ans1 = LittleEndian(hex(addMod2_32(A, IV_A))[2:-1], True).zfill(8)
ans2 = LittleEndian(hex(addMod2_32(B, IV_B))[2:-1], True).zfill(8)
ans3 = LittleEndian(hex(addMod2_32(C, IV_C))[2:-1], True).zfill(8)
ans4 = LittleEndian(hex(addMod2_32(D, IV_D))[2:-1], True).zfill(8)
return ans1 + ans2 + ans3 + ans4
def main():
m = input("请输入明文: ")
ans = MD5(m)
print("明文加密后的密文是:\n" + MD5(m) + " (Lowercase)\n" + ans.upper() + " (Uppercase)")
if __name__ == '__main__':
main()
|
