A riddle, wrapped up in a mystery, inside an enigma

Looking for a way to make sure your pesky little brother doesn't read your diary? Need a way to make those notes you pass in class completely undecipherable, even if intercepted by a teacher?

Well, here's a solution. For a limited time only (the next 7 days), one of the original Enigma cipher machines is available for public purchase on Ebay. That's right. A piece of remarkable cryptological history is up for sale on an online auction site, right there with Beanie Babies and autographed pictures of the Spice Girls.

What is an Enigma machine? Wikipedia has a great history of the Enigma, but in short, it was a cipher machine used by the Germans during World War II. The machine operates on the basic principle of a substitution cipher (A=Z, B=Y, C=X, etc.) but instead of just having this basic substitution, rotors within the machine would turn whenever a key was pressed, changing the cipher key. It's a pretty cool idea (yes, I realize that's an understatement), and one that makes messages encoded by the Enigma extremely challenging to crack, particularly in the days before computers.

Several Polish cryptographers were able to crack the Enigma in 1932, primarily because the Germans made mistakes like using the same starting position on the machine for a long time or letting a codebook fall into enemy hands. Cracking the Enigma machine was a real asset to the Allied war effort.

If you're interested in seeing one of these machines, there are quite a few still in existence, and some are scattered at museums throughout the country. The one on display at the National Cryptologic Museum at the NSA headquarters in Ft. Meade, Maryland is particularly cool because you can play around with it and encode and decode your own messages. I've been there--it's pretty fun (although the rest of the museum isn't too much to write home about).

So, now that you're all excited to get one of these machines and start encoding messages of your own, care to know how much the Ebay asking price is? Well, the current price is $28,000, plus $65 to ship it from Italy to the US; the reserve has been met, so now it's just a question of how much people out there are willing to spend.

Honestly, $28,000 doesn't seem all that bad to me. If I had loads of money to toss around, I'd much rather spend it on a cool, working code machine that some piece of crap modern art that costs millions of dollars. But maybe that's just me...