Staganography

I came across a new word today – Steganography. I wondered what it means, and started looking for more information. And this is what I learnt.

“”Steganography is the art and science of writing hidden messages in such a way that no one apart from the intended recipient knows of the existence of the message; this is in contrast to cryptography, where the existence of the message itself is not disguised, but the meaning is obscured. The name comes from Johannes Trithemius's Steganographia: a treatise on cryptography and steganography disguised as a book on black magic, and is Greek ("στεγανογραφία") for "hidden writing." -- http://en.wikipedia.org/wiki/Steganography

Steganography has a very ancient origin. I read a story of a message tattooed on a slave’s shaved head, covered by his hair re-growth, and exposed by re-shaving. It was also used by various secret agents, during and post-World War.

I realized there is a great benefit of Steganography in the modern times. This technique can be used to watermark the images – unknowingly. You would not be able to see the watermark unless you run the image through a program. You know the origin of the picture. It can be applied to pictures posted on the internet etc.

I came across another, rather, abuse of this technique.

Flickr is a great photo-blogging site. A pro account gives you unlimited data storage. But all you can store is pictures. Nothing else. People started experimenting with the steganographic techniques to store all kinds of data, under the cover of a jpg file in their flickr accounts. As data storage does not have any limit, it can work as a ‘virtual online backup’. Of course, people would notice the abnormal size of the pictures etc, but I leant that currently the website does not restrict uploading such files. What happens if everyone wants to use these sites as virtual backup sites? Do the websites know about it? Are they willingly allowing it initially so that they can become popular?

Leaving these questions for the websites, I think steganography is a great idea. I think Dan Brown’s “The Da Vinci Code”’s anagrams can be termed as steganographic too. Fun.