On: JPEG canaries: exposing on-the-fly recompression

[slavak]

Like someone commented on the site itself, I also can see a faint outline of the hidden message in the original (left) image. It changes in clarity if I change the angle I'm viewing my LCD screen at - most visible when I view it from below (which darkens the screen).

[jarin → slavak]

It also changes from visible to invisible if you scroll one pixel up or down (although this may depend on your monitor).

I suspect though that it would be almost impossible to detect on a photo (the typical use case for JPEGs).

[Sniffnoy → slavak]

I can see it too. But now the question is - would we have been able to notice it if we didn't already know it was there?

[dustingetz → slavak]

i think the intended application is when printed then photocopied.