Function main

src/gamesbyexample/affinecipher.py:20–69

()

def main():
    print('''Affine Cipher, by Al Sweigart al@inventwithpython.com
The affine cipher is a simple substitution cipher that uses addition and
multiplication to encrypt and decrypt symbols.''')

    # Let the user specify if they are encrypting or decrypting:
    while True:  # Keep asking until the user enters e or d.
        print('Do you want to (e)ncrypt or (d)ecrypt?')
        response = input('> ').lower()
        if response.startswith('e'):
            myMode = 'encrypt'
            break
        elif response.startswith('d'):
            myMode = 'decrypt'
            break
        print('Please enter the letter e or d.')

    # Let the user specify the key to use:
    while True:  # Keep asking until the user enters a valid key.
        print('Please specify the key to use,')
        print('or RANDOM to have one generated for you:')
        response = input('> ').upper()
        if response == 'RANDOM':
            myKey = generateRandomKey()
            print('The key is {}. KEEP THIS SECRET!'.format(myKey))
            break
        else:
            if not response.isdecimal():
                print('This key is not a number.')
                continue
            if checkKey(int(response), myMode):
                myKey = int(response)
                break

    # Let the user specify the message to encrypt/decrypt:
    print('Enter the message to {}.'.format(myMode))
    myMessage = input('> ')

    if myMode == 'encrypt':
        translated = encryptMessage(myKey, myMessage)
    elif myMode == 'decrypt':
        translated = decryptMessage(myKey, myMessage)
    print('%sed text:' % (myMode.title()))
    print(translated)

    try:
        pyperclip.copy(translated)
        print('Full %sed text copied to clipboard.' % (myMode))
    except:
        pass  # Do nothing if pyperclip wasn't installed.


def getKeyPartsFromKey(key):