Show HN: A novel approach to detect image manipulation | Hacker News Reader

Show HN: A novel approach to detect image manipulation

github.com

36 pointsdennis-tra6 comments

Pretty neat idea! Being able to highlight exactly which areas of a photo were modified is much better than an image-wide "pass/fail."

Sadly the "doesn't survive compression/re-encoding" problem is kind of a show-stopper. I think steganography still has some important usecases, like covertly sending messages, but I don't think it's practical for "watermarking" images that are expected to be widely distributed.

btw, I noticed that the Merkle tree package you're using doesn't use a distinguisher bit in its node hashes: https://github.com/cbergoon/merkletree/blob/master/merkle_tr...

This can be a security issue in some contexts, since it means you can construct a leaf and a pair of nodes that have the same hash.

Thanks for your comment!

> Sadly the "doesn't survive compression/re-encoding" problem is kind of a show-stopper

Indeed, that’s true - fortunately there are already ways to at least limit the problem. There is some research under the umbrella of “robust JPEG steganography” which aims to persist the covert message among compression. But I don’t know how well this actually works. LSB steganography was just the most straight forward way for me to implement.

Thanks for pointing out the security issue - I certainly wouldn’t have noticed it!

Looks like this could also work to invisibly watermark or "sign" images, in such a way that doesn't affect the way they display.

If you want to embed a public key in an image, there's https://github.com/lukechampine/jsteg/tree/master/cmd/slink

Pretty cool, but dude @denis-tra, it's the sixth time you've submitted this link in less than two months (https://news.ycombinator.com/from?site=github.com/dennis-tra)

Hi huxflux,

Thanks for your comment and I’m glad you liked it. Your remark is true and I was concerned as well. However the HN FAQs state:

> Are reposts ok?

> If a story has not had significant attention in the last year or so, a small number of reposts is ok.

I consider 6 as a “small number” and “significant attention” certainly > 4 upvotes (the most upvotes of a previous post) - YMMV.

Reply on news.ycombinator.com