我将如何在python中实现vigenere密码

Question

I was tasked to create a caesar cipher in the past and now I am trying to implement the viginere cipher in python. I want to know how I would go about doing this. I have a basic idea of using variables from the user as 'plaintext' and the alphabet as its own variable and then adding them to create its own variable and using the index from these in the alphabet and the line of code:

cipher += alphabet[(alphabet.index(c)+key) % (len(alphabet))

This perhaps may be wrong.

Answer 1

The following comes from Rosetta Code 's web site:

from itertools import starmap, cycle

def encrypt(message, key):

    # convert to uppercase.
    # strip out non-alpha characters.
    message = filter(lambda _: _.isalpha(), message.upper())

    # single letter encrpytion.
    def enc(c,k): return chr(((ord(k) + ord(c)) % 26) + ord('A'))

    return "".join(starmap(enc, zip(message, cycle(key))))

def decrypt(message, key):

    # single letter decryption.
    def dec(c,k): return chr(((ord(c) - ord(k)) % 26) + ord('A'))

    return "".join(starmap(dec, zip(message, cycle(key))))

An example showing how to use the code is included:

text = "Beware the Jabberwock, my son! The jaws that bite, the claws that catch!"
key = "VIGENERECIPHER"

encr = encrypt(text, key)
decr = decrypt(encr, key)

print text
print encr
print decr

Finally, we can see what output of running the code should be:

Beware the Jabberwock, my son! The jaws that bite, the claws that catch!
WMCEEIKLGRPIFVMEUGXQPWQVIOIAVEYXUEKFKBTALVXTGAFXYEVKPAGY
BEWARETHEJABBERWOCKMYSONTHEJAWSTHATBITETHECLAWSTHATCATCH