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.
In this chapter, let us understand how to implement Vignere cipher. Consider the text This is basic implementation of Vignere Cipher is to be encoded and the key used is PIZZA.
Code
可以使用以下代码在 Python 中实现韦格纳密码：
You can use the following code to implement a Vignere cipher in Python −
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()