密码学课程设计之MD5

#coding:utf-8
import math
def str_bin(string):
	a = ''
	for i in string:
		f = bin(ord(i))[2:]
		f = '0'*(8-len(f)) + f
		a += f
	return a
def Little_Endian(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

def T(i):
	res = (int(4294967296*abs(math.sin(i))))&0xffffffff
	return res
def addMod32(a,b):
	return (a+b)%(2**32)
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))

def MD5(m):
	iv_A = 0x67452301
	iv_B = 0xefcdab89
	iv_C = 0x98badcfe
	iv_D = 0x10325476
	s_list = [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]
	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)))
	L = lambda x,n:(((x<<n)|(x>>32-n)))&(0xffffffff)
	m = str_bin(m)
	lm = len(m)
	lm_mod = lm%512
	if lm_mod == 448:
		f_length = 512
	elif lm_mod > 448:
		f_length = 512 + 448 - lm_mod
	else:
		f_length = 448 - lm_mod
	m += '1' + (f_length-1)*'0'
	m_padding =  Little_Endian(bin(lm%(2**64))[2:].zfill(64),False)
	m += m_padding
	lm = len(m)
	A, B, C, D = iv_A, iv_B, iv_C, iv_D
	for i in range(0,lm,512):
		Y = m[i:i+512]
		A1, B1, C1, D1 = A, B, C, D
		for j in range(4):
			for k in range(16):
				AA, BB, CC, DD = A, B, C, D
				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 = Little_Endian(Y[M[j][k]*32:M[j][k]*32+32],False)
				A, C, D = DD, BB, CC 
				B = addMod32(AA,t)
				B = addMod32(B,int(M_j,2))
				B = addMod32(B,T_i)
				B = L(B,s_list[16*j + k])
				B = addMod32(B,BB)
		A = addMod32(A,A1)
		B = addMod32(B,B1)
		C = addMod32(C,C1)
		D = addMod32(D,D1)
	ans1 = Little_Endian(hex(A)[2:-1],True).zfill(8)
	ans2 = Little_Endian(hex(B)[2:-1],True).zfill(8)
	ans3 = Little_Endian(hex(C)[2:-1],True).zfill(8)
	ans4 = Little_Endian(hex(D)[2:-1],True).zfill(8)
	return ans1+ans2+ans3+ans4

m = 'cumt'
print "明文：%s\nMD5加密：%s"%(m,MD5(m).upper())