Tuesday, August 26, 2008

Work Work Work - StegoFS demo

So things have been super busy as of late, and there is not much sign of things letting up. I still hope to release something from the new StegoFS project, but I'm scheduled to be in many different places in the next few months.

I have had a few folks contact me about the video I demonstrated at DEFCON 16. I choose a video from youtube (that awful HACKERS movie) because at the time I was testing how consistent youtube was in compressing audio and video that it had already processed. Also, it's nice to choose something with aspect ratio bars--that way I can demo a barcode style watermark where you can see it (how to demonstrate something designed to be hidden is problematic . . .). Plus, it was handy to use a video that unlikely to be watched. http://www.youtube.com/watch?v=djhWj19aWAA or just search youtube for "OMG HACKERS"--at least right now it is the top result.

So if you check it out, you may want to use an FLV recorder such as real player. In this example, the coded data is just hexadecimal FF in even hamming code, in triplicate. I chose to use grey as ones and leave black as zeros just to make it easier to read. Watch the video for a while, and notice how youtube's compression manipulates the encoded bits worse when there is a lot of bright activity on the screen. But all we have to do is average them out, maybe add a little more redundancy, then we are good to go--mostly. :)

You may want to use an accessability tool like xzoom to zoom in on the coded part of the video.

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