There are k! substitution ciphers for an alphabet with k letters—too many for an exhaustive search. With a frequency-based approach adapted to the graph of alphabetic ciphers, we redefine the act of deciphering as a sampling problem suitable for a Metropolis-Hastings random walk. A substitution cipher is thus solvable with a Markov chain. Let’s begin… Continue reading Solve a Substitution Cipher with a Markov chain