"If you want to hide something securely, leave it on your own." Using this method, the spies of the past were actively rewritten using invisible ink, which manifested itself only with the help of the necessary chemical reagents. In the digital age, this technology has an analog - in the ordinary text of the messenger, characters with the tag "invisibility" and zero width are built in so that the user can not read them without a decoder.

Researchers from Columbia University engaged in the development of the concept and developed a "Fontcode" - the technology of data encryption in the text, which also works when printing it on plain paper. To do this, the encoder program translates the original message into a sequence of numbers, which are then converted into parameters for correcting a typical font. Here the letter for a pixel is much fatter to draw, there just below the put, here the interval for a couple of pixels is narrowed, etc.

For the human eye this is the most common text, but it's worth scanning it with a smartphone camera and skipping through the decoder as we get the encoded message. Everything works very simply, although the method has a big flaw - if you open the coded text in a regular editor, it simply automatically "fix" it and erases all the characters. It's a shame, and on the other hand, that's automatic protection against interception of information.

The authors of the study do not work on local spies, they are enthusiastic scientists. And so they see the application of Fontcode in another sphere - for example, so you can implement a watermark for printing important documents. Or include in the text of the intracorporate order secret items that will be visible only to authorized employees, to protect against industrial espionage. There are many options, but most importantly, the principle of invisible ink is still relevant.