Cryptography With Python 简明教程

Hacking Monoalphabetic Cipher

在本章中,您将了解单表字母加密及其使用 Python 进行破解。

Monoalphabetic Cipher

单表字母加密对加密整个消息使用固定的替换。此处显示了使用带有 JSON 对象的 Python 字典的单表字母加密−

monoalpha_cipher = {
   'a': 'm',
   'b': 'n',
   'c': 'b',
   'd': 'v',
   'e': 'c',
   'f': 'x',
   'g': 'z',
   'h': 'a',
   'i': 's',
   'j': 'd',
   'k': 'f',
   'l': 'g',
   'm': 'h',
   'n': 'j',
   'o': 'k',
   'p': 'l',
   'q': 'p',
   'r': 'o',
   's': 'i',
   't': 'u',
   'u': 'y',
   'v': 't',
   'w': 'r',
   'x': 'e',
   'y': 'w',
   'z': 'q',
	' ': ' ',
}

借助此字典,我们可以用作为 JSON 对象中值的关联字母来加密字母。以下程序创建了一个单表字母程序,作为一个类表示,其中包括所有加密和解密的函数。

from string import letters, digits
from random import shuffle

def random_monoalpha_cipher(pool = None):
   if pool is None:
      pool = letters + digits
   original_pool = list(pool)
   shuffled_pool = list(pool)
   shuffle(shuffled_pool)
   return dict(zip(original_pool, shuffled_pool))

def inverse_monoalpha_cipher(monoalpha_cipher):
   inverse_monoalpha = {}
   for key, value in monoalpha_cipher.iteritems():
      inverse_monoalpha[value] = key
   return inverse_monoalpha

def encrypt_with_monoalpha(message, monoalpha_cipher):
   encrypted_message = []
   for letter in message:
      encrypted_message.append(monoalpha_cipher.get(letter, letter))
   return ''.join(encrypted_message)

def decrypt_with_monoalpha(encrypted_message, monoalpha_cipher):
   return encrypt_with_monoalpha(
      encrypted_message,
      inverse_monoalpha_cipher(monoalpha_cipher)
   )

此文件稍后被调用来实现单表字母加密的加密和解密过程,如下所示−

import monoalphabeticCipher as mc

cipher = mc.random_monoalpha_cipher()
print(cipher)
encrypted = mc.encrypt_with_monoalpha('Hello all you hackers out there!', cipher)
decrypted = mc.decrypt_with_monoalpha('sXGGt SGG Nt0 HSrLXFC t0U UHXFX!', cipher)

print(encrypted)
print(decrypted)

Output

当您实现上面给出的代码时,可以看到以下输出−

monoalphabetic

因此,您可以破解具有指定键值对的单表字母加密,该键值对将密码文本破解为实际的明文。