Hidden in plain sight

Steganography, or steg as it’s usually called among my colleagues, is more or less a way to hide things in plain sight. I see steg in my work and occasionally I encounter it in geocaching, normally it’s used in the clues of a unknown cache but this time it was used for the cache itself and it was so well done that I just had to tell about it. Although I’m not showing pictures that can’t be seen on the cache page itself, this could still be considered a spoiler, so if you plan on geocaching in Stockholm; Spoiler alert!

So, what exactly is steganography? Imagine finding a letter that’s obviously encrypted, you would instantly know there is something secret in there and if you are the problem-solving kind of person you would probably try and decode it just to get to the information. Also if you visit US I think the 4^th amendment to the constitution say in a way that encrypted files found on your computer must be decrypted when requested by police or military, otherwise you might face a two year imprisonment. Steg is not encryption, but it can be bundled with encryption. Steg is a way to hide the information in such way that unless you know it’s there you won’t see it, even if you are looking straight at it. In the digital sphere where I work, steg is usually made by manipulating pixels in a picture or other media, and with the right key you can pick out just the changes and put them together to reveal the original message. One of the first known uses of steg was a written warning about the Persian invasion of Greece. A slave’s head was shaved, the warning tattooed into the scalp. And once the hair had grown out again he was sent to Greece. Also during World War II, the French Resistance sent messages written with invisible ink on the backs of the couriers that carried normal, innocent letters.

Back to geocaching and the cache we found in Stockholm, what exactly had it to do with geocaching? Well, one of the reasons caches are hidden is so muggles won’t find them and destroy them, but the cache we found was visible from far away if you knew what to look for. To be honest I think that if they had tried to hide the cache in a normal way, like a magnetic can on the backside of a sign, it would have been destroyed long time ago. The place for the geocache was an advertising signpost for the “Moderna museet”, a museum with modern art, and it was made in such a way that you could not distinguish it from the signpost itself. They modified the art, without destroying it, in such way that only the creator would instantly know something had changed. No wonder this is the geocache in Sweden with most favorite points, almost twice as many as number two on the list.

Can you see it?