|
|
|
|
|
|
by chongli
4577 days ago
|
|
|
The question is: would it be feasible to search for them? Scan every single video on youtube looking for noise with some elevated probability of containing hidden text? What happens when you find a candidate? Pick random pixels out of every frame and then try and brute force it with every known symmetric cipher and every single key? You could flip a single, random, least-significant bit on each frame of a 1 hour movie. This would allow you to store a 10.5KB encrypted message within. I'd like to know how anyone could possibly find those bits, let alone decipher them. |
|
|
If I'm the Secret Police in some oppressive state, then I just need to find out whether you seem to be using stego — which is naturally against the law, itself, and hence grounds for arrest. Then, I can use rubber hoses, bamboo splinters, the threat of violence against your loved ones, and what-not to "brute force" your passphrase.
If I'm the NSA, I just detect the presence of stego and stash the container for later — say, when my quantum computer finally works as advertised, or I can plant a keylogger or turn on the back door on the your computers and sniff your passphrase, or simply mine your social graph until I find some other means of compromising you.
The possibilities are hardly limited to a naïve, brute-force search across the set of (crypto algorithm, passphrase) tuples.
EDIT: But, to your point: yes, using video makes finding stego harder. It doesn't change the nature of the problem, though; it just changes its scale. Against adversaries with the computational power of a modern nation-state, however, if you're relying on scale to hide your behavior, licit or otherwise, you're only deluding yourself.