Шифр цезаря и криптоаналитическая атака

from random import *
import string
 
Alphalist = list("ABCDEFGHIJKLMNOPQRSTUVWXYZ")
file = open('текст для теса.txt', 'r')
startMessage = file.read().upper()
startMessage = startMessage.translate(str.maketrans(' ', ' ', string.punctuation))  # избавились от знаков препинания
print("Текст для зашифровки:", startMessage)
numberkey = int(input('Отступ: '))
key=[Alphalist[randint(0,len(Alphalist))-1]for i in range(1,len(Alphalist))]
key=set(key)
key=''.join(list(key))
print('Ключевое слово:',key)
 
 
def remove(alpha, string):
    for symbol in string:
        if symbol not in [chr(x) for x in range(65, 91)] \
        or string.count(symbol) > 1: string.remove(symbol)
        if symbol in alpha: alpha.remove(symbol)
    return alpha, string
 
 
def insert(alpha_string):
    for index, symbol in enumerate(alpha_string[1]):
        alpha_string[0].insert((numberkey + index) % 26, symbol)
    return alpha_string[0]
 
 
def encryptDecrypt( message, keyy,final=""):
    alpha = insert(remove(Alphalist, key))
    print(alpha)
    for symbol in message:
            final += alpha[(alpha.index(symbol) + keyy) % 26]
    return final
def encryptDecrypt1( message, keyy,final1=""):
    alpha = insert(remove(Alphalist, key))
    print(alpha)
    for symbol in message:
            final1 += alpha[(alpha.index(symbol) - keyy) % 26]
    return final1
 
 
message = encryptDecrypt( startMessage, numberkey)
 
print("Final", message)
EngAlphabet = [[' ', 0.185], ['e', 0.097], ['t', 0.076], ['a', 0.064], ['o', 0.062], ['n', 0.057], ['i', 0.056],
               ['s', 0.052], ['r', 0.047], ['h', 0.04], ['l', 0.031], ['d', 0.028], ['c', 0.025], ['u', 0.018],
               ['p', 0.018], ['f', 0.018], ['m', 0.017], ['w', 0.016], ['y', 0.015], ['b', 0.013], ['g', 0.013],
               ['v', 0.007], ['k', 0.0039], ['q', 0.002], ['x', 0.002], ['j', 0.001], ['z', 0.001]]
 
CryptAlphabet = []
for i in set(''.join(list(message))):
    CryptAlphabet.append([i, message.count(i) / len(message)])
 
for i in range(len(CryptAlphabet) - 1):
    for j in range(len(CryptAlphabet) - i - 1):
        if CryptAlphabet[j][1] < CryptAlphabet[j + 1][1]:
            CryptAlphabet[j], CryptAlphabet[j + 1] = CryptAlphabet[j + 1], CryptAlphabet[j]
 
LetterSwap = []
for i in range(len(EngAlphabet)):
    LetterSwap.append([EngAlphabet[i][0], CryptAlphabet[i][0]])
 
Run = True
while Run:
    EncryptWord = ""
    for letter in message:
        for i in LetterSwap:
            if letter == i[1]:
                EncryptWord += i[0]
                break
 
    print('расшифрованный текст:', EncryptWord)