Function decryptMessage

src/gamesbyexample/railfencecipher.py:118–139

(message, key)

def decryptMessage(message, key):
    rails = getBlankRails(message, key)
    railCoordinates = getRailCoordinates(message, key)

    # Lay out the letters on the rails:
    messageIndex = 0
    for railNumber in range(key):
        for x, y in railCoordinates:
            if y == railNumber:
                rails[x][y] = message[messageIndex]
                messageIndex += 1

    # Read the letters in rail order:
    decryptedText = ''
    for x, y in railCoordinates:
        decryptedText += rails[x][y]

    # Show the decrypted message to the user:
    displayRails(rails)
    print('The decrypted message is:')
    print(decryptedText)
    copyIfPossible(decryptedText)


# If this program was run (instead of imported), run the game: