MCS _425: The History and analysis of the Playfair and ADFGX Ciphers - Brian Kozeny

Sources: The Code Breakers The Story of Secret Writing pdf- https://www.google.com/search?q=the+code+breakers+free+pdf&oq=the+code+breakers+free+pdf&aqs=chrome..69i57j0i10i22i30i457.7778j0j15&sourceid=chrome&ie=UTF-8 Introduction to Cryptography with Coding Theory (2nd Edition) pdf - https://isidore.co/calibre/get/pdf/4971 Crypto Corner.com - https://crypto.interactive-maths.com/ Practical Cryptography. com - http://practicalcryptography.com/ciphers/adfgx-cipher/ Frequency Analysis Information - http://www.viviancook.uk/SpellStats/DigFreqs.html The frequency of double-letters in Cryptoquotes by Rick Wicklin - https://blogs.sas.com/content/iml/2014/10/10/frequency-of-double-letters-in-quotes.html