My friend F and I used to send each other coded messages. Without ever telling each other what cipher was used, though – figuring out how to decipher the message was the main source of entertainment, the actual content of the message was never important.

The first ciphers were fairly easy, like simple substitution ciphers. But then after a while we both started writing programs to both cipher and decipher, because the more complex the systems got, the less fun it was to go through the tables or transformations for every single letter that needed to be coded or decoded. And then after a while we stopped.

Now, years later, I came across these brilliant instructions for building an Enigma.

So this is what I did over Christmas:

And then, obviously, I had to decipher stuff. Luckily my dad is as fond of these kind of games as I am! And – as I found out earlier this week – some of my colleagues are completely and utterly fascinated by this kind of stuff, too.

Check it out, it is fun! :-)