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Full Version: is saving as JPG safe enough ?
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I've got some photos with my personal information and some photos which I want to implement my copyright logo onto it. After hiding the details or adding the logo and EXPORTING them as JPG/JPEG. Are those photos safe enough to be distributed ? Any possibility of the recovering the hidden message from my photo?
(Sep 24, 2014 18:32)ofnuts Wrote: [ -> ]What kind of "personal information"? Something like the licence plate of the car in the picture? Or the camera serial number in the file metadata?

I know XCF is not safe. Layer can be removed and the confidential information will be revealed. But how about JPG? Does JPG itself contain layers? Does it ''DELETE'' the hidden information permanently?


(Sep 24, 2014 21:37)ofnuts Wrote: [ -> ]Yes, from that point of view, whatever you cannot see on the JPG cannot be recovered, assuming it has been completely obliterated and not just transformed using a predictable algorithm(*). Personally I use "Filters>Noise>Spread..." because it masks letters very nicely without making the masking stick out too much(**):

(*) several years ago a pedophile got identified because he hid his face on pictures using the equivalent of Gimp's whirl & pinch and there are algorithms to de-whirl/de-pinch.

(**) it just exchanges pixels at random, so the overall lightness/color doesn't change. Make the horizontal spread cover three character widths or more.

predictable algorithm??

What did you mean?

I often (and actually always) hide the message completely with a full-filled rectangular box, will that be sufficient? (and saving as JPG/JPEG of course) And, btw, what is the difference between JPG and JPEG
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