Python Task 2 Single Keyword Encryption

def getMode():
    while True:
        print("Do you wish to encrypt[1] or decrypt[2]")
        mode = input("Please enter '1' or '2': ")
        if mode == '1' or mode == '2':
            return mode
        else:
            print("Invalid")




def getMessage():
    message = input("message: ")
    print("Message accepted")
    return message



def keyword():
    while True:
        keyword = input("Keyword: ")
        check = keyword.isalpha()
        if check == True:
            print("Keyword accepted!")
            return keyword
        else:
            print("Keyword invalid, try again")


def makeList():
    counter = 0
    for char in keyword:
        letter = keyword[counter]
        letterList.append(letter)
        counter += 1
    return letterList

def crypt():
    newMessage = ''
    counter = 0
    for char in message:
        if char.isalpha():
            num = ord(char)
            num2 = ord(letterList[counter])
            if mode == '1':
                newNum = num + num2 - 64
            elif mode == '2':
                newNum = num - num2 + 64
            while newNum > ord('Z'):
                newNum -= 26
            while newNum < ord('A'):
                newNum += 26
            newChar = chr(newNum)
            newMessage += newChar
            counter += 1
            if counter >= length:
                counter = 0
            else:
                counter = counter
        else:
            newMessage += char
    return newMessage


mode = getMode()
message = getMessage()
message = message.upper()
keyword = keyword()
length = len(keyword)
letterList = []

letterList = makeList()
newMessage = crypt()
print("Your new message is", newMessage)
input("Press enter to end program")