【转】DES加密算法的Python实现

#coding=utf-8   

from functools import partial   

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()   
    
    
if __name__ == ‘__main__’:   
    d = DES()   
    d.input_key(‘密码8位!’)   
    s = ‘这是原文\n’  
    a = d.encode(s)   
    print a   
    b = d.decode(a)   
    print b

转自:http://www.oschina.net/code/snippet_70229_2618

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