All of us have asked our best friend to keep a secret, but if our best friend is a geek, he might have thought of encrypting the information. Encryption is the process of transforming clear text into something that cannot be understood without the right key. For instance, Julius Cesar used a simple cipher (i.e., encryption algorithm) which is to replace every letter by the third following letter in the alphabet (the key is "third letter" and it could have been any other number). There is a lot to be said about encryption but today's topic is even more interesting because steganography is the process of keeping the information in clear but in a way that, if you don't know what you are looking for, you won't find it. Ancient greeks used it, Al Qaeda uses it, and flickr and twitter can use it.
