Python基于DES算法加密解密实例

本文实例讲述了Python基于DES算法加密解密实现方法。分享给大家供大家参考。具体实现方法如下：

    #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

希望本文所述对大家的Python程序设计有所帮助。