The Vigenère Cipher Encryption and Decryption - Python

vigenere.py

######## Made By Mouad Khiat
######## This script is the Famous Vigenere cipher its like caesar that ive made in the previous gist
######## but the difference is that we deal here with letters not numbers
######## So with this script you can encrypt anything you want with your given key , decrypt it either with a key or a part of it
######## or by guessing

from random import sample
from itertools import product as col


def generator(key,char,length):
    char_len = key.count(char)   
    key_piece = key[:length - char_len:]
    list_keys = [key_piece+"".join(i) for i in list(col([chr(i) for i in range(65, 65+26)], repeat=char_len))]
    return list_keys
	
def vigenere(x,key):
    lst_final = []
    code = list(x)
    j = 0
	
    for i,char in enumerate(code):
        if char.isalpha():
            code[i] = key[(i+j)%len(key)]
            if encrypt:
                lst_final.append((ord(x[i]) + ord(code[i]) - 65 * 2) % 26)
            else:
                lst_final.append((ord(x[i]) - ord(code[i])) % 26)
        else:
            lst_final.append(ord(char))
            j -=1

    for i,char in enumerate(code):
        if char.isalpha():
            lst_final[i] = chr(lst_final[i] + 65)
        else:
            lst_final[i] = chr(lst_final[i])
			
    return ''.join(lst_final)

print("Welcome to Vigenere cipher")

if input('Encrypt or Decrypt : ').lower() == 'encrypt':
    x = input('Enter the text : ').upper()
    key = input('Enter the key : ').upper()
    encrypt = True
    print(vigenere(x,key))
else:
    x = input('text : ').upper()
    encrypt = False
    if input('have you the key (y/n) : ') == "y":
        key = input('Enter the key : ').upper()
        print(vigenere(x,key))
    else:
        abc = list("ABCDEFGHIJKHIJKLMNOPQRSTUVWXYZ")
        question = input('Enter a part of the key or length (answer by 1 or 2 or nothing): ')
        if question == '1':
            key = input('*use \'?\' for the missing letter in the key (C?? or CL? refer for ex to CLE): ').upper()
            list_of_keys = generator(key,'?',len(key))
            for k in list_of_keys:
                print(f'for {k} ==> {vigenere(x,k)}')
			
        elif question == '2':
            length = int(input('Enter the length: '))
            while True:
                key_gen = ''.join(sample(abc,length))
                print(f"for {key_gen} = {vigenere(x,key_gen)}")
                if input('continue(y/n) ... : ')== "n":
                    break
        else:
            print("S0rry this script cannot find your encrypted text")