steganography, for fun and ... backup?

[khedron]

Steganography is the art of hiding one message inside another. It's been used to hide secrets for thousands of years, often in plain sight. This paper describes how steganography works using modern techniques to hide data inside images so that they're undetectable. The paper is especially good because it has a postscript about steganography throughout history, and includes my favorite oft-cited example:

One of the oldest stego schemes was to shave the head of a messenger and tattoo a message on the messenger's head. After the hair grows back, the messenger can be sent to the intended recipient, where the messenger's head can be shaved and the message recovered. This method is decidingly clever, patient, and very low-tech, and goes right to the heart of steganography's literal meaning of "covered writing."

I don't know if I buy this, it sounds like an exceedingly slow form of message passing, but on the flip side, this is usually attributed to "the Romans", and it certainly took longer to get around back then...

Anyway. The point of this is to link to this article in which a guy has decided steganography + flickr = free backup. This is a wacky thing to do -- even wackier than the people who use gmail as a file system -- and takes "hiding information in plain sight" to a whole new level. I wonder if he plans on flickr tagging the images so he can find them again?

Comments

[crouchback.livejournal.com]

This wasn't done by the Romans, it was done by Persians. Herodotus mentions it.

And so Aristagoras was not able to fulfil his
promise to Artaphrenes; and at the same time he was hard pressed by
the demand made to him for the expenses of the expedition, and had
fears because of the ill success of the armament and because he had
become an enemy of Megabates; and he supposed that he would be
deprived of his rule over Miletos. Having all these various fears he
began to make plans of revolt: for it happened also that just at this
time the man who had been marked upon the head had come from Hisiaios
who was at Susa, signifying that Aristagoras should revolt from the
king. For Histiaios, desiring to signify to Aristagoras that he should
revolt, was not able to do it safely in any other way, because the
roads were guarded, but shaved off the hair of the most faithful of
his slaves, and having marked his head by pricking it, waited till the
hair had grown again; and as soon as it was grown, he sent him away to
Miletos, giving him no other charge but this, namely that when he
should have arrived at Miletos he should bid Aristagoras shave his
hair and look at his head: and the marks, as I have said before,
signified revolt. This thing Histiaios was doing, because he was
greatly vexed by being detained at Susa. He had great hopes then that
if a revolt occurred he would be let go to the sea-coast; but if no
change was made at Miletos[20a] he had no expectation of ever
returning thither again.