Avoid online censorship with 'Collage' and hide your data with Flickr

University graduate designs way to subvert censorship and possibly even the dreaded internet filter.

Internet censorship is a topic that we're certainly keeping a close eye on here at Atomic, since freedom online is something that many of us take for granted - though not something we're willing to give up without a fight.

New Scientist reports that a team of university graduates at the Georgia Institute of Technology in Atlanta have created a solution that they've dubbed 'Collage', and as the name implies, it relies on services such as Flickr to function as it predominantly works with photographs.

Collage uses a form of digital steganography to encode news stories, other text messages or whatsoever their heart desires - and insert that data directly into a .jpg file using an automated process.

Digital steganography is a highly complex form of encryption that is best summarised by Information Security Magazine:

"...data is first encrypted by the usual means and then inserted, using a special algorithm, into redundant (that is, provided but unneeded) data that is part of a particular file format such as a JPEG image. Think of all the bits that represent the same color pixels repeated in a row. By applying the encrypted data to this redundant data in some random or nonconspicuous way, the result will be data that appears to have the "noise" patterns of regular, nonencrypted data."

Once the image has been uploaded to Flickr, along with the hidden data, subscribers to that particular photostream can download the file and extract the message contained within, as seen in the diagram below via the team's paper (PDF):

A desktop application encodes message data down the left column, and decodes it up the right., in each case using digital steganography.

It also appears that the team behind Collage have been successful in their tests, with their project page explaining, "Our evaluation of Collage shows that the performance overhead is acceptable for sending small messages (e.g., Web articles, email)...By hiding data inside user-generated content as they traverse the network, Collage escapes detection by censors."

A working build of Collage is due to be released imminently at the USENIX Security Symposium.