• Published on | Aug 29, 2016 | by Chris Osborn

Another Retro Challenge Has Arrived: CauzCoin!

It's been a while since I did a retro challenge since they tend to be quite a bit of work to put together. The last two used modems and my BBS as the heart of the challenge, with the first one simply requiring dialing in with a real modem, and the second one requiring a little more work by decoding a secret message and running some special software. This time around the data won't be encoded as audio, but it will definitely be no less interesting with considerable effort involved.
After figuring out how the Cauzin Softstrip barcodes are encoded and being able to finally create my own, I thought it would be a fun challenge to put something inside of a barcode and post it publicly to give people a reason to pull out their Cauzin readers, or possibly even motivate someone to write some software to decode without using any special hardware at all.
What to place inside of a barcode though? I can't encode something physical in it, so that means no vinyl decal like the two retro movie themed ones I did last time (if you missed out you can still get the WarGames and Real Genius decals in my store). Maybe some kind of picture? A special program that plays a song? Maybe a gift card? The gift card idea doesn't seem too bad. But instead of a gift card that's only good at one store, how about something with no national boundaries like Bitcoin. That seems like an interesting idea!
The challenge is pretty simple, at least on the surface. I've created a PDF with a Cauzin Softstrip on it, and encoded in the barcode data is a Bitcoin private key. But it's not just as simple as that. The key isn't just plain text and will require additional sleuthing to extract.
I'm starting off the prize at a value of $5 US. If after 24 hours no-one has claimed the prize then I will add another $5. I will keep doing that each day until the value reaches $25 or the prize is claimed, whichever comes first. That means that you can either decode it and claim it right away, or wait for more funds to be added and hope that no-one else claims the prize before you do.
If you enjoy challenges like this, let me know! I enjoy making them even though it always seem to take a lot more work than I anticipate so hearing how much fun everyone had makes it worth it!

Update Sep 1, 2016: 

The prize was claimed at $15. Will Sowerbutts on reddit was able to solve the puzzle! Thanks to everyone for inspiring me to do this challenge, and a big thanks to David Glover-Aoki for providing the Bitcoin funds for the prize!


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