3 ms·
While I agree in principle, this is a 310x146 pixel, 1-bit image that's 360KB in size. It's pretty obvious that there's a payload in there somewhere. For comp
by danielbarla 12y ago
While I agree in principle, this is a 310x146 pixel, 1-bit image that's 360KB in size. It's pretty obvious that there's a payload in there somewhere.
For comparison, recompressed as a normal PNG, it's 9.5KB, and even saving it as a 32-bit BMP is less than half the original size (at around 176KB). I don't know how this kind of thing "scales", but if I'm asked to download a 50MB PNG, I get suspicious. I'm pretty sure anyone you'd want to employ this against would be at least that sophisticated.
- diafygi 12y agoThe 360K filesize is because I wanted to update the image to include the real iv in the image, which is based on the filesize. The only way to do that was to leave the PNG uncompressed (so the filesize remained constant), making the PNG you see 180K plus a duplicate reverse encrypted version appended at the end of the file, making the total 360K.
- danielbarla 12y agoI see, although that is still about 20x larger than the normal equivalent. What I'm saying is two-fold; with this technique, simply checking the image's metadata and comparing to the size gives you an easy way to identify interesting images, the ones likely to contain a hidden messages. And second, this kind of "low signal to noise" ratio seems to be applicable to most steganography techniques. If I need to send 50MB of junk (and convincing junk at that) to get 1MB of message through, I'm going to have to question the value the stego provides (since it provides even more data and evidence that there's something to hide, especially if it's easily identifyable, as in this case). Still interesting, just not quite as awesome as everyone seems to think.