Readers of a certain age will remember those 'invisible ink' spy toys that let you write a 'secret' message which would only appear after rubbing the page with half of a lemon. Yeah, this is not that.

Ink containing polymers that can store data has been used to write a letter containing a hidden message – the encryption key to unlock a text file of L. Frank Baum’s The Wonderful Wizard of Oz. Eric ...

Cryptography, in the dictionary, is the art of writing or solving codes. In the security world, its the practice and study of techniques for secure communication in the presence of third parties ...