Python DES-based encryption and decryption instance

This article mainly introduces Python's Implementation Method of encryption and decryption Based on the DES algorithm, and analyzes the related skills of the DES algorithm in the form of examples, for more information about how to implement Python's DES-based encryption and decryption, see the example in this article. Share it with you for your reference. The specific implementation method is as follows:

# Coding = UTF-8 from functools import partial import base64 class DES (object): "DES encryption algorithm interface: input_key (s, base = 10), encode (s ), decode (s) "" _ ip =,, 24, 39,] _ ip1 = [, 1, 58,26, 33,1, 41, 9,49, 17,57, 25,] _ e = [32, 1, 2, 3, 4, 5, 4, 5, 6, 7, 8, 9, 8, 13, 12, 13, 15, 16, 17, 16, 17, 18, 19, 20, 21, 20, 21, 24, 25, 24, 25, 26, 27, 28, 29, 28, 29, 30, 31, 32, 1,] _ p = [16, 17, 1, 26, 2, 8, 24, 14, 3, 9, 19,13, 30, 6, 22, 11,] _ s = [[0xe, 0x4, 0xd, 0x2, 0xf, 0xb, 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, 0x9, 0x5, 0xb, 0x3, 0xe, 0xa, 0x6, 0xd,], [0xf, 0x8, 0xe, 0x6, 0xb, 0x2, 0xd, 0xc, 0x5, 0xa, 0x3, 0xd, 0x4, 0x7, 0xf, 0x2, 0x8, 0xe, 0xc, 0x0, 0x 1, 0xa, 0x6, 0x9, 0xb, 0x5, 0x0, 0xe, 0x7, 0xb, 0xa, 0x4, 0xd, 0x5, 0x8, 0xc, 0x6, 0x9, 0x3, 0x2, 0xf, 0xd, 0x8, 0xa, 0x3, 0xf, 0x2, 0xb, 0x6, 0x7, 0xc, 0x5, 0xe, 0x9,], [0xa, 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, 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, 0x3, 0xe, 0x5, 0x8, 0x4, 0x3, 0xf, 0x0 0x6, 0xa, 0x1, 0xd, 0x8, 0x9, 0x4, 0x5, 0xb, 0xc, 0x7, 0x2, 0xe,], [0x2, 0xc, 0x7, 0xa, 0xb, 0x6, 0x8, 0x5, 0x3, 0xf, 0xd, 0x0, 0xe, 0x9, 0xe, 0xb, 0x2, 0xc, 0x7, 0xd, 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, 0x9, 0xa, 0x5, 0x3,], [0xc, 0x1, 0xa, 0xf, 0x9, 0x2, 0x6, 0x8, 0x0, 0x3, 0x4, 0xe, 0x7, 0x5, 0xb, 0xa, 0xf, 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, 0x2, 0xc, 0x9, 0x5, 0xf, 0xa, 0xb, 0xe, 0x6, 0x0, 0x8, 0xd,], [0x4, 0xb, 0x2, 0xe, 0xf, 0x0 0 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, 0x9, 0xc, 0xe, 0x0x6, 0xa, 0xd, 0xf, 0x3, 0x5, 0x8, 0x2, 0x1, 0xe, 0x7, 0x4, 0xa, 0x8, 0xd, 0xf, 0xc, 0x9, 0x0 0x3, 0x5, 0x6, 0xb,],] _ k1 = [, 49, 9, 1, 10,, 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, 2,] _ k0 =, 0000, 0001,] _ hex_bin = {'0': '20170', '1': '20170', '2 ': '123', '3': '123', '4': '123', '5': '123', '6': '123', '7 ': '000000', '8': '000000', '9': '000000', 'A': '000000', 'B': '000000', 'C ': '000000', 'D': '000000', 'E': '000000', 'F': '000000 ','': '000000'} _ 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 (h Ex_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 _ ini T _ (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 = 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. rstrip (). decode ('utf-8') if _ name _ = '_ main _': d = DES () d. input_key ('000000') s = 'Next to a Chinese character 'a = d. encode (s) print a B = d. decode (a) print B

I hope this article will help you with Python programming.