Poly-Alphabetic Substitution Cipher Tools
This page demonstrates a variety of tools to use with the poly-alphabetic substitution cipher systems.
To crack a poly-alphabetice cipher you need to guess the repeat length of the codeword used.
If it isn't based on a keyword then you need a "crib." A crib is a word or phrase that is very likely to be in the message.
alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"