API tools faq
paste
Advertisement
Guest User

Untitled

a guest
Jan 19th, 2018
104
0
Never
Add comment
Not a member of Pastebin yet? Sign Up, it unlocks many cool features!
Python 8.43 KB | None | 0 0
raw download clone embed print report
  1. #-*- coding: utf8 -*-
  2. import base64
  3. '''
  4. Sources :
  5. https://www.tutorialspoint.com/cryptography/data_encryption_standard.htm
  6. https://en.wikipedia.org/wiki/DES_supplementary_material
  7. http://homepage.usask.ca/~dtr467/400/
  8. '''
  9.  
  10. '''Constantes du DES'''
  11.  
  12. #Permutation initiale (IP)
  13.  
  14. PI = [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]
  15.  
  16. #Permutation finale (IP-1)
  17. PI_1 = [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]
  18.  
  19. #Développement (E) matrice d'expansion (expand)
  20. 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]
  21.  
  22. #Permutation (P)
  23. 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]
  24.      
  25. #Permuted choice 1 (PC-1)
  26. CP1 = [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]
  27.        
  28. #Permuted choice 2 (PC-2)
  29.  
  30. CP_2 = [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]
  31.        
  32. #Ces deux permutations PC1 et PC2 serviront à créer les 16 sous-clés de 48 bits qui seront utiles dans le réseau de Feistel.
  33.  
  34.  
  35. #Boîtes de substitution SBOX
  36. SBOX = [
  37.          
  38. [[14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7],
  39.  [0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8],
  40.  [4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0],
  41.  [15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13],
  42. ],
  43.  
  44. [[15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10],
  45.  [3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5],
  46.  [0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15],
  47.  [13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9],
  48. ],
  49.  
  50. [[10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8],
  51.  [13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1],
  52.  [13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7],
  53.  [1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12],
  54. ],
  55.  
  56. [[7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15],
  57.  [13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9],
  58.  [10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4],
  59.  [3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14],
  60. ],  
  61.  
  62. [[2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9],
  63.  [14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6],
  64.  [4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14],
  65.  [11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3],
  66. ],
  67.  
  68. [[12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11],
  69.  [10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8],
  70.  [9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6],
  71.  [4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13],
  72. ],
  73.  
  74. [[4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1],
  75.  [13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6],
  76.  [1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2],
  77.  [6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12],
  78. ],
  79.    
  80. [[13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7],
  81.  [1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2],
  82.  [7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8],
  83.  [2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11],
  84. ]
  85. ]
  86.  
  87.  
  88.  
  89. #Décalage dans la création des sous-clés selon le numero d'iteration (round)
  90. SHIFT = [1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1]
  91.  
  92.  
  93.  
  94. '''Convertir une string à une liste de bits'''
  95. def stringToBit(text):
  96.     l = list()
  97.     for char in text:
  98.         binval = binvalue(char, 8)
  99.         l.extend([int(x) for x in list(binval)])
  100.     return l
  101.  
  102.  
  103. '''Convertir une liste de bits à une string'''
  104. def bitToString(liste):
  105.     result = ''.join([chr(int(j,2)) for j in [''.join([str(i) for i in bytes]) for bytes in  splitList(liste,8)]])
  106.     return result
  107.  
  108.  
  109. '''Diviser une liste à un ensemble de liste de taille n'''
  110. def splitList (lst, n):
  111.     it = iter(lst)
  112.     new = [[next(it) for _ in range(n)] for _ in range(len(lst) // n)]
  113.     for i, x in enumerate(it):
  114.         new[i].append(x)
  115.     return new
  116.  
  117.  
  118.  
  119. '''Donner la valeur binaire de taille n d'une string '''
  120. def binvalue(string, n):
  121.     binval = bin(string)[2:] if isinstance(string, int) else bin(ord(string))[2:]
  122.     while len(binval) < n:
  123.         binval = "0"+binval
  124.     return binval
  125.  
  126.  
  127.  
  128. '''Permuter un block en utilisant une liste donné en paramétre'''
  129. def permut(block, liste):#
  130.     p = []
  131.     for i in liste:
  132.         p.append(block[i - 1])
  133.     return p
  134.  
  135.  
  136.  
  137. '''Decalage gauche selon n bit'''
  138. def shift(g, d, n):
  139.     shifted = (g[n:] + g[:n], d[n:] + d[:n])
  140.     return shifted
  141.  
  142. '''Comme permuter juste une redefinition pour la clareté'''
  143. def expand(block, liste):#
  144.     p = []
  145.     for i in liste:
  146.         p.append(block[i - 1])
  147.     return p
  148.  
  149.  
  150. '''Fonction XOR'''
  151. def xor(t1, t2):
  152.     return [x^y for x,y in zip(t1,t2)]
  153.  
  154.  
  155. '''Substituer en utilisant les s-box 6 bits ==> 4 bits'''
  156. def substitute(de):
  157.     subblocks = splitList(de, 6)
  158.     result = list()
  159.     for i in range(len(subblocks)):
  160.         block = subblocks[i]
  161.         row = int(str(block[0])+str(block[5]),2)
  162.         column = int(''.join([str(x) for x in block[1:][:-1]]),2)
  163.         val = SBOX[i][row][column]
  164.         bin = binvalue(val, 4)
  165.         result += [int(x) for x in bin]
  166.     return result
  167.  
  168. '''PKCS5 padding longuer block = 8'''
  169. def addPadd(data):
  170.     pad_len = 8- (len(data)%8)
  171.     data += pad_len * chr(pad_len)
  172.     return data
  173.  
  174.  
  175. '''Supprimer le padding en cas d'utilisation'''
  176. def removePadd(data):
  177.     pad_len = ord(data[-1])
  178.     return data[:-pad_len]
  179.  
  180.  
  181. #liste pour sauvegarder les clés généreés
  182. keys = list()
  183.  
  184. '''Génération des clés'''
  185. def generate_keys(key):
  186.     key = stringToBit(key)
  187.     key = permut(key, CP1)
  188.     g, d = splitList(key, 28)
  189.     for i in range(16):
  190.         g, d = shift(g, d, SHIFT[i])
  191.         merge = g + d
  192.         permut2 = permut(merge, CP_2)
  193.         keys.append(permut2)
  194.  
  195.  
  196. '''Opération de chiffrement'''
  197. def encrypt(key ,text):
  198.     if padding:
  199.         text = addPadd(text)
  200.     # Generation des clés
  201.     generate_keys(key)
  202.  
  203.     text_blocks = splitList(text, 8)
  204.     print(text_blocks)
  205.     result = list()
  206.     for block in text_blocks:
  207.         block = stringToBit(block)
  208.         block = permut(block, PI)
  209.         g, d = splitList(block, 32)
  210.         for i in range(16):
  211.             de = expand(d, E)
  212.             t = xor(keys[i], de)
  213.  
  214.             t = substitute(t)
  215.             t = permut(t, P)
  216.             t = xor(g, t)
  217.             g = d
  218.             d = t
  219.         result += permut(d + g, PI_1)
  220.     finalRes = bitToString(result)
  221.     return finalRes
  222.  
  223.  
  224.    
  225. def cbc_enc(text,key,IV):
  226.    
  227.     f = ""
  228.  
  229.     text_blocks = splitList(text, 8)
  230.     for block in text_blocks:
  231.         block = stringToBit(block)
  232.  
  233.         print(block)
  234.         tmp = xor(block,IV)
  235.         c =encrypt(key,tmp)
  236.         f+=c
  237.         IV = c
  238.     return f
  239.  
  240.  
  241. test1 = list()
  242.  
  243. def cbc_dec(f,IV):
  244.     ol = ""
  245.     text_blocks = splitList(f, 8)
  246.     for block in text_blocks:
  247.         print(block)
  248.         a = decrypt(block)
  249.         tmp = xor(stringToBit(block),IV)
  250.         ol+=bitToString(tmp)
  251.         IV = block
  252.     return ol
  253.  
  254.    
  255.  
  256.  
  257.  
  258. '''Opération de déchiffrement'''
  259. def decrypt(text):
  260.     text_blocks = splitList(text, 8)
  261.     #print(text_blocks)
  262.     result = list()
  263.     for block in text_blocks:
  264.         block = stringToBit(block)
  265.         block = permut(block, PI)
  266.         g, d = splitList(block, 32)
  267.         for i in range(16):
  268.             de = expand(d, E)
  269.             t = xor(keys[15 - i], de)
  270.             t = substitute(t)
  271.             t = permut(t, P)
  272.             t = xor(g, t)
  273.             g = d
  274.             d = t
  275.         result += permut(d + g, PI_1)
  276.     finalRes = bitToString(result)
  277.     if padding:
  278.         return removePadd(finalRes)
  279.     else:
  280.         return finalRes
  281.  
  282.  
  283. key = "secret_k"
  284. text= "TESTTEST"
  285. IV = stringToBit('a')
  286. print(IV)
  287. padding = False
  288.  
  289. a = cbc_enc(text,key,IV)
  290. cipher = base64.b64encode(a)
  291. b = cbc_dec(a,IV)
  292.  
  293. print(a)
  294. print(b)
Advertisement
Add Comment
Please, Sign In to add comment
Advertisement
Public Pastes
Advertisement
We use cookies for various purposes including analytics. By continuing to use Pastebin, you agree to our use of cookies as described in the Cookies Policy.  OK, I Understand
Not a member of Pastebin yet?
Sign Up, it unlocks many cool features!