Cryptography With Python 简明教程

Implementing Vignere Cipher

在本章中，让我们了解韦格纳密码的实现方式。考虑要对文本 This is basic implementation of Vignere Cipher 进行编码，所使用的密钥为 PIZZA.

Code

可以使用以下代码在 Python 中实现韦格纳密码：

import pyperclip

LETTERS = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
def main():
   myMessage = "This is basic implementation of Vignere Cipher"
   myKey = 'PIZZA'
   myMode = 'encrypt'

   if myMode == 'encrypt':
      translated = encryptMessage(myKey, myMessage)
   elif myMode == 'decrypt':
      translated = decryptMessage(myKey, myMessage)

   print('%sed message:' % (myMode.title()))
   print(translated)
   print()
def encryptMessage(key, message):
   return translateMessage(key, message, 'encrypt')
def decryptMessage(key, message):
   return translateMessage(key, message, 'decrypt')
def translateMessage(key, message, mode):
   translated = [] # stores the encrypted/decrypted message string
   keyIndex = 0
   key = key.upper()

   for symbol in message:
      num = LETTERS.find(symbol.upper())
      if num != -1:
         if mode == 'encrypt':
            num += LETTERS.find(key[keyIndex])
				elif mode == 'decrypt':
               num -= LETTERS.find(key[keyIndex])
            num %= len(LETTERS)

            if symbol.isupper():
               translated.append(LETTERS[num])
            elif symbol.islower():
               translated.append(LETTERS[num].lower())
            keyIndex += 1

            if keyIndex == len(key):
               keyIndex = 0
         else:
            translated.append(symbol)
      return ''.join(translated)
if __name__ == '__main__':
   main()

Output

当您实现上面给出的代码时，可以看到以下输出−

破解韦格纳密码的可能组合近乎不可能。因此，它被认为是一种安全的加密模式。