Over the past several months, I’ve started playing Google’s Ingress, a mobile-phone based video game which is cross between capture the flag and a militant version of foursquare. One of the key features of the game is “decoding” secret messages hidden in documents and media given to the players that can be redeemed for special supplies. This prompted an interest in what I call “puzzle cryptography”: identifying and solving puzzles which incorporate elements of classical cryptography systems. And as regular readers of this blog are aware, once we get interested: Python programs get written…
Puzzle cryptography is based on testing methods and spotting clues vs. a more formal “rigorous” approach to cryptography associated with military and security applications. You’re presented with a snippet of material – generally text or images containing text – and called upon to extract a code from that material. Many snippets would actually be viewed as unsolvable in traditional cryptography: they are too short for statistical techniques and usually designed to defeat letter frequency and word pattern analysis. They are, however, a lot of fun to fiddle around with. The purpose of this article is to walk you through some of the common types of “obfuscation” which can be done to a message using classical cryptography and introduce tools to make the process easier.
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