Hidden information in screenshots?

[zork]

Took some screenshots of models in my viewer.

Thought there is sth on my monitor at first:


Nope. It is in the image.


I remember reading about that kind of stuff long time ago. Maybe just fragments from the TGA to JPEG algorithm.

Or is that to find out who leaked WoW alpha images to the press? That would make sense at least. I would watermark my images in alpha state aswell.

*edit*

Tested it. Information is not included in TGA screenshots and JPG screenshots at quality 10. All other screenshots include that kind of fragments. Fragments seem to differ depending on chosen quality.

[def9]

I remember reading about this kind of thing a while back. If I remember right its called steganalysis if you want to research it further.

[Duugu]

You could test some less uniform backgrounds. What are the results?

[Nynaeve]

Just wondering, have you tested this using a program to screencapture (fraps, etc)? Or are you using the default in-game screenshot hotkey? Would be interesting to know if there are any differences in the screencapture between the two methods.

[Duugu]

He did them ingame. And it is a watermark.

TOM_RUS postet a link to a deeper description. But the post is deleted now!? Don't know if he did this or if the link was against the wowi rules?

[Vlad]

It's a bit odd that the post with the link to ownedcore was deleted.

I mean the content linked was a real thread on this topic. It contains relevant and educational information and Java/C# code to make your own image scanning tool to read this kind of data from your own screenshots.

In any case it's a watermark put on "low" quality jpegs to appear as artifacts, but it contains your wow account name (pre bnet), server name and IP. Basic info to combat private servers I reckon.

[TOM_RUS]

Originally Posted by Duugu He did them ingame. And it is a watermark. TOM_RUS postet a link to a deeper description. But the post is deleted now!? Don't know if he did this or if the link was against the wowi toc?

Admin removed it.

[Cairenn]

It was a link to a hack site. Those are against Blizzard's rules. We are an official fansite. We follow Blizz rules, in order to maintain official fansite status. Thus, link removed.

[Phanx]

I don't know about the rest of the site, as I'd never heard of it before, but I found the research thread about the screenshot watermarking pretty interesting, as well as further eroding my trust in Blizzard after all the other things they've done to indicate a total lack of regard for my privacy. There's some info about the watermarking (and a link to the original thread) in this article on Kotaku, which -- being a well-known general gaming news site -- should be acceptable to post links to here.

[semlar]

This is super old and if I remember correctly it was to help blizzard trace leaks from alpha servers or identify whether a screenshot came from a private server.

[Vlad]

I upload a snippet of the parts I think you'll find interesting regarding this subject:
http://i.imgur.com/f8QiVxt.png

I hope making a image of the content isn't against any rules. :P

[Resike]

So this means all the screenshots i have taken in the past 10 years are fckd up. This method might be also in Warcraft 3 too.

[Vlad]

Not quite. If you read the thread it should say something about this appearing around The Burning Crusade. I doubt they used this for WC3 or any game before that.

Also this doesn't appear if you use anything else than JPG or if you use JPG but set the quality to the maximum 10. The watermark only appears on low resolution, anything below 10.

[Yafis]

Originally Posted by Vlad Not quite. If you read the thread it should say something about this appearing around The Burning Crusade. I doubt they used this for WC3 or any game before that. Also this doesn't appear if you use anything else than JPG or if you use JPG but set the quality to the maximum 10. The watermark only appears on low resolution, anything below 10.

Ого, первый русский человек которого я нашел тут

[Vlad]

Sorry Yafis. I'm Norwegian.

But perhaps TOM_RUS is Russian, not sure though. Names can be misleading. :P