“Secretbook” extension can encode hidden messages in Facebook pictures

Posted at 11:18 AM, Apr 10, 2013
and last updated 2013-04-10 11:18:49-04

A 21-year-old Oxford University computer science student and former Google intern has released a Google Chrome browser extension this week that allows you to encode images uploaded to Facebook with secret messages.

Owen Campbell-Moore released Secretbook after spending two months working on the extension as a research project for the university.

The secret messages are limited to 140 characters and can only be unlocked through a password you create, keeping them safe from prying eyes in the company, government or anyone else.

This marks the first time someone has been able to automate digital steganography (the practice of concealing messages inside computer files,) through Facebook.

Steganographic messages are hidden where no one would think to look, such as in a single pixel changed and repeated. However, when an image is uploaded to Facebook, it’s automatically compressed, which would garble the secret message.

Campbell-Moore was able to replicate Facebook’s compression algorithm and minimize the amount of change in order to not damage the secret message.