Python基于DES算法加密解密实例

#coding=utf-8 
from functools import partial 
import base64 
class DES(object): 
 """ 
 DES加密算法 
 interface: input_key(s, base=10), encode(s), decode(s) 
 """ 
 __ip = [ 
 58,50,42,34,26,18,10,2,60,52,44,36,28,20,12,4, 
 62,54,46,38,30,22,14,6,64,56,48,40,32,24,16,8, 
 57,49,41,33,25,17, 9,1,59,51,43,35,27,19,11,3, 
 61,53,45,37,29,21,13,5,63,55,47,39,31,23,15,7, 
 ] 
 __ip1 = [ 
 40,8,48,16,56,24,64,32,39,7,47,15,55,23,63,31, 
 38,6,46,14,54,22,62,30,37,5,45,13,53,21,61,29, 
 36,4,44,12,52,20,60,28,35,3,43,11,51,19,59,27, 
 34,2,42,10,50,18,58,26,33,1,41, 9,49,17,57,25, 
 ] 
 __e = [ 
 32, 1, 2, 3, 4, 5, 
 4 , 5, 6, 7, 8, 9, 
 8 , 9,10,11,12,13, 
 12,13,14,15,16,17, 
 16,17,18,19,20,21, 
 20,21,22,23,24,25, 
 24,25,26,27,28,29, 
 28,29,30,31,32, 1, 
 ] 
 __p = [ 
 16, 7,20,21,29,12,28,17, 
 1 ,15,23,26, 5,18,31,10, 
 2 ,8 ,24,14,32,27, 3, 9, 
 19,13,30, 6,22,11, 4,25, 
 ] 
 __s = [ 
 [ 
 0xe,0x4,0xd,0x1,0x2,0xf,0xb,0x8,0x3,0xa,0x6,0xc,0x5,0x9,0x0,0x7,
 0x0,0xf,0x7,0x4,0xe,0x2,0xd,0x1,0xa,0x6,0xc,0xb,0x9,0x5,0x3,0x8,
 0x4,0x1,0xe,0x8,0xd,0x6,0x2,0xb,0xf,0xc,0x9,0x7,0x3,0xa,0x5,0x0,
 0xf,0xc,0x8,0x2,0x4,0x9,0x1,0x7,0x5,0xb,0x3,0xe,0xa,0x0,0x6,0xd,
 ], 
 [ 
 0xf,0x1,0x8,0xe,0x6,0xb,0x3,0x4,0x9,0x7,0x2,0xd,0xc,0x0,0x5,0xa,
 0x3,0xd,0x4,0x7,0xf,0x2,0x8,0xe,0xc,0x0,0x1,0xa,0x6,0x9,0xb,0x5,
 0x0,0xe,0x7,0xb,0xa,0x4,0xd,0x1,0x5,0x8,0xc,0x6,0x9,0x3,0x2,0xf,
 0xd,0x8,0xa,0x1,0x3,0xf,0x4,0x2,0xb,0x6,0x7,0xc,0x0,0x5,0xe,0x9,
 ], 
 [ 
 0xa,0x0,0x9,0xe,0x6,0x3,0xf,0x5,0x1,0xd,0xc,0x7,0xb,0x4,0x2,0x8,
 0xd,0x7,0x0,0x9,0x3,0x4,0x6,0xa,0x2,0x8,0x5,0xe,0xc,0xb,0xf,0x1,
 0xd,0x6,0x4,0x9,0x8,0xf,0x3,0x0,0xb,0x1,0x2,0xc,0x5,0xa,0xe,0x7,
 0x1,0xa,0xd,0x0,0x6,0x9,0x8,0x7,0x4,0xf,0xe,0x3,0xb,0x5,0x2,0xc,
 ], 
 [ 
 0x7,0xd,0xe,0x3,0x0,0x6,0x9,0xa,0x1,0x2,0x8,0x5,0xb,0xc,0x4,0xf,
 0xd,0x8,0xb,0x5,0x6,0xf,0x0,0x3,0x4,0x7,0x2,0xc,0x1,0xa,0xe,0x9,
 0xa,0x6,0x9,0x0,0xc,0xb,0x7,0xd,0xf,0x1,0x3,0xe,0x5,0x2,0x8,0x4,
 0x3,0xf,0x0,0x6,0xa,0x1,0xd,0x8,0x9,0x4,0x5,0xb,0xc,0x7,0x2,0xe,
 ], 
 [ 
 0x2,0xc,0x4,0x1,0x7,0xa,0xb,0x6,0x8,0x5,0x3,0xf,0xd,0x0,0xe,0x9,
 0xe,0xb,0x2,0xc,0x4,0x7,0xd,0x1,0x5,0x0,0xf,0xa,0x3,0x9,0x8,0x6,
 0x4,0x2,0x1,0xb,0xa,0xd,0x7,0x8,0xf,0x9,0xc,0x5,0x6,0x3,0x0,0xe,
 0xb,0x8,0xc,0x7,0x1,0xe,0x2,0xd,0x6,0xf,0x0,0x9,0xa,0x4,0x5,0x3,
 ], 
 [ 
 0xc,0x1,0xa,0xf,0x9,0x2,0x6,0x8,0x0,0xd,0x3,0x4,0xe,0x7,0x5,0xb,
 0xa,0xf,0x4,0x2,0x7,0xc,0x9,0x5,0x6,0x1,0xd,0xe,0x0,0xb,0x3,0x8,
 0x9,0xe,0xf,0x5,0x2,0x8,0xc,0x3,0x7,0x0,0x4,0xa,0x1,0xd,0xb,0x6,
 0x4,0x3,0x2,0xc,0x9,0x5,0xf,0xa,0xb,0xe,0x1,0x7,0x6,0x0,0x8,0xd,
 ], 
 [ 
 0x4,0xb,0x2,0xe,0xf,0x0,0x8,0xd,0x3,0xc,0x9,0x7,0x5,0xa,0x6,0x1,
 0xd,0x0,0xb,0x7,0x4,0x9,0x1,0xa,0xe,0x3,0x5,0xc,0x2,0xf,0x8,0x6,
 0x1,0x4,0xb,0xd,0xc,0x3,0x7,0xe,0xa,0xf,0x6,0x8,0x0,0x5,0x9,0x2,
 0x6,0xb,0xd,0x8,0x1,0x4,0xa,0x7,0x9,0x5,0x0,0xf,0xe,0x2,0x3,0xc,
 ], 
 [ 
 0xd,0x2,0x8,0x4,0x6,0xf,0xb,0x1,0xa,0x9,0x3,0xe,0x5,0x0,0xc,0x7,
 0x1,0xf,0xd,0x8,0xa,0x3,0x7,0x4,0xc,0x5,0x6,0xb,0x0,0xe,0x9,0x2,
 0x7,0xb,0x4,0x1,0x9,0xc,0xe,0x2,0x0,0x6,0xa,0xd,0xf,0x3,0x5,0x8,
 0x2,0x1,0xe,0x7,0x4,0xa,0x8,0xd,0xf,0xc,0x9,0x0,0x3,0x5,0x6,0xb,
 ], 
 ] 
 __k1 = [ 
 57,49,41,33,25,17, 9, 
 1 ,58,50,42,34,26,18, 
 10, 2,59,51,43,35,27, 
 19,11, 3,60,52,44,36, 
 63,55,47,39,31,23,15, 
 7 ,62,54,46,38,30,22, 
 14, 6,61,53,45,37,29, 
 21,13, 5,28,20,12, 4, 
 ] 
 __k2 = [ 
 14,17,11,24, 1, 5, 3,28, 
 15, 6,21,10,23,19,12, 4, 
 26, 8,16, 7,27,20,13, 2, 
 41,52,31,37,47,55,30,40, 
 51,45,33,48,44,49,39,56, 
 34,53,46,42,50,36,29,32, 
 ] 
 __k0 = [ 
 1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1, 
 ] 
 __hex_bin = { 
 '0':'0000','1':'0001','2':'0010','3':'0011', 
 '4':'0100','5':'0101','6':'0110','7':'0111', 
 '8':'1000','9':'1001','a':'1010','b':'1011', 
 'c':'1100','d':'1101','e':'1110','f':'1111', 
 ' ':'0000' 
 } 
 __re = lambda t, s: ''.join(s[i-1] for i in t) 
 __IP = partial(__re, __ip) 
 __IP1 = partial(__re, __ip1) 
 __E = partial(__re, __e) 
 __P = partial(__re, __p) 
 __K1 = partial(__re, __k1) 
 __K2 = partial(__re, __k2) 
 __B = partial( lambda hex_bin, s: ''.join(hex_bin[w] 
 for w in ''.join('%2x' % ord(w) for w in s)) 
 , __hex_bin) 
 __DB = partial( lambda s: ''.join(chr(int(s[i:i+8], 2)) for i in range(0, len(s), 8))) 
 __S = partial( lambda hex_bin, __s, s: ''.join(hex_bin['%x' % __s[i][ 
 int(s[i*6]+s[i*6+5], 2)*16 + int(s[i*6+1:i*6+5], 2)]] for i in range(8)) 
 , __hex_bin, __s) 
 __F = partial( lambda s, k: ''.join('0' if s[i]==k[i] else '1' for i in range(len(s)))) 
 __K0 = partial( lambda k0, K2, k: map(K2, 
 (k[k0[i]:28]+k[0:k0[i]] + k[k0[i]+28:56]+k[28:k0[i]+28] for i in range(16))) 
 , __k0, __K2) 
 __K = partial( lambda K1, K0, k: K0(K1(k)) 
 , __K1, __K0) 
 def __init__(self): 
 pass 
 def input_key(self, key, base=10): 
 if base == 2: 
 pass 
 elif base == 16: 
 key = ''.join(self.__class__.__hex_bin[w] for w in key) 
 else: 
 key = self.__class__.__B(key) 
 self.__k = self.__class__.__K(key) 
 def __code(self, s, k): 
 s = self.__IP(s) 
 l, r = s[0:32], s[32:64] 
 for i in range(16): 
 r_t = r 
 r = self.__E(r) 
 r = self.__F(r, k[i]) 
 r = self.__S(r) 
 r = self.__P(r) 
 r = self.__F(r, l) 
 l = r_t 
 return self.__class__.__IP1(r+l) 
 def encode(self, s): 
 a = '' 
 s += ' ' * ((8-len(s)%8)%8) 
 for i in range(0, len(s), 8): 
 before = self.__class__.__B(s[i:i+8]) 
 after = self.__code(before, self.__k) 
 a += '%16x' % int(after, 2) 
 return ''.join(w if w!=' ' else '0' for w in a) 
 def decode(self, s): 
 a = '' 
 s.lower() 
 for i in range(0, len(s), 16): 
 before = ''.join(self.__class__.__hex_bin[s[j]] for j in range(i, i+16)) 
 after = self.__code(before, self.__k[::-1]) 
 a += self.__class__.__DB(after) 
 return a.rstrip().decode('utf-8') 
if __name__ == '__main__': 
 d = DES() 
 d.input_key('123456789') 
 s = '再来一段中文' 
 a = d.encode(s) 
 print a 
 b = d.decode(a) 
 print b