Risk of exposure from using digital cameras and photoediting software

[nbk2000]

According to an article at http://graphicssoft.about.com/b/a/2003_07_26.htm the hostess of TechTV, Cat Schwartz, was exposed (literally) when a picture she had cropped using (presumably) photoshop left a recoverable thumbnail image of the original photo that showed her boobs.

:)

This is bad for us pyros, though, since it may be possible to recover an indentifable face from a digitally edited photo if you are sloppy in the way you save it.


Thumbnail previews are part of the EXIF metadata that all digital cameras embed into JPEG files.


That's NOT good.

However, Photoshop's Save for Web command strips out the extra metadata and thumbnail previews automatically, so I'm quite safe since that's the only way I save pictures anyways, as well as being aware of my own presence in pictures so that I'm not caught in reflections or as shadow. :)

The rest of you may wish to keep this possible risk in mind next time you take a snapshot. ;)

[GibboNet]

I've been using "save for web" for it's good compression / quality, but it seems it's much more useful.

I assume that saving in different formats would also correct the problem. I use Irfanview to save a lot of images. Especially in photoshop, when I don't want to flatten an image, just make a preview in gif, for the web. It can load all photoshop images, and save to any format. Very handy piece of soeftware.

If I had a digital camera, I'd be more worried, but not for a while yet. :(

Is the thumbnail useful to, say cops trying to identify you ? A thumbnail is only tiny, and would hopefully not be large enough to make out a clear image. I would have thought someone from "TechTV" would have known better.

[chemwarrior]

Gibbo, with the technology they have, they can magnify the thumbnail considerably with virtually no loss of image quality. However, I dont think they would be able to use that as evidence, but Im safe since I dont use a digital camera..

Speaking of pictures, NBK, those photos I promised you the other day should be here tommorrow (I did the cheap ass photo devlopment that takes them like a week and half to get around to.. lol)

[megalomania]

Well lets say someone had such a cropped photo, how does one go about viewing the thumbnail? I would like to be able to check some pictures of mine, and other pics to check for myself. I would imagine this flaw could also be useful to oridinary people, imagine a pic with a liscense plate blurred, or a face, or something. We might not be able to do as good a job as the feds (who actually contract image enhancement to NASA), but there is probably some good software out there.

[nbk2000]

I'd try either the picture browser in PS7, or use an EXIF viewer, as linked to in the article.

You shouldn't expect a pretty talking head of a computer show to know anything about the products she talks about. That's not what she's there for. She is there to provide eye candy and a pleasant voice to read the script off the teleprompter, nothing more.

This also shows how you can get caught up by things that you're not aware of, if you're not careful and RTPB "Plan for Failure". You have to figure on "Them" being able to eventually reverse anything you do to a picture/video, so you have to plan accordingly when taking pics/video to not include ANYTHING that could identify you.

You know how videos have the faces blocked out with mosaic? I know how it can be reversed, but it takes major computing power and specific circumstances, but that's not the point, the point being that it CAN be done, and will get better every year at doing so.

Just like when you shred papers, you can't rely solely on that, you have to use it in addition to fire to ensure destruction. :) Layers upon layers, that's the key to security. ;)

[flashpoint]

Just like when you shred papers, you can't rely solely on that, you have to use it in addition to fire to ensure destruction.

I actually do this, in some circumstances...although I don't think its necessary for myself at the time, although I do not know, personally if I've been watched or trailed in a way. NBK, I never knew that mosaic could be reversed, I guess they flip-flop all the pictures around, until they fit. I'm going to go search for some documentation on that...

[DimmuJesus]

There is always a risk in doing anything through digital technology and computer, imaging not excluded. I have read forensic stories about how people have been tracked by FBI tech teams by actually finding information coded into files. For example, in an image when you save it, it might possibly leave a digital fingerprint of your computer coded into the file itself. Not as a metadata but as a part of the file itself.
Anything you do on your computer, look at or read online, even stuff you delete is at risk of being recovered later. Sometimes even destroying the harddrive itself isn't enough, because a lot of ISPs and web services store so much online. Like MSN, most of your history and other things are actually stored online, not on your computer. I try to make it a habit to keep anything that I want completely personal away from any type of technology. It just makes it so darn hard because in many ways I am a tech nerd and love how convenient and easy things can be made through the use of a computer.
There is a different discussion about PGP and how safe that is. If Big Brother really wants access to something, he'll get it. Uncle Sam has all the time and resourses he needs to decrypt anything.

[junk12]

This topic seems worth to be ressurected- after 2 years.

Original and uncropped pictures of Cat Schwartz can be seen at http://old.fuckallyall.com/article1585.html.

The reason for resurrection was, that I recently encountered at similar reverse engineering-antiblurring.
Nbk2k has already mention that, but on can be seen detailed explanation. With dictionary attack(brute force), one can go trough all possible pixel permutations of blurred area and on each of them execute same blur effect. If new blurred picture matches original blurred picture, then picture is possible blurred original of original blurred picture. Of course we get several candidates and the winner is one, which makes sense, when we look at http://dheera.net/projects/blur.php. Here is still one minor problem. We have to know the one way algorithm with which,
original picture was blurred. I hope this make sense to you.

In generally, more complex thing is, more things can go wrong. Simple is best :) . For example, if one save picture in base format like bmp, there is no special coding in meta file, and when picture is changed, that is irreversible(from picture data), but in formats like jpg, there is always encoding, with regard to original picture. Same with pdf formats. Sometimes when one have several pages and deletes a few, file size might increase. That's because pdf file is being just partly changed and not encoded from the scratch.

And Chemwarrior, magnifying picture is sci-fi, because there is lost data, which can not be gained (except if there is some redundant data). This magnifying thing really bothers me, when I watch it in the movies - though sci-fi.

Note: Because my post had to been revised, which took more than 24 hours, I couldn't edit it. Please if one of moderators delete my previus post. I still didn't figure it out, why both of links didn't show.

[Match]

Did anybody else click on that link in hopes to see her tits :D

[knowledgehungry]

In regards to magnification/improving quality of a video/picture; A year or two ago a police officer was shot and killed. The killer was caught on a crappy security camera tape moments before shooting the cop. The original video was released almost immediately after the shooting to try to find the shooter. It was very low quality and hard to make anything out, they sent the video to the FBI guys, and after a week the improved quality video was shown. The difference was not that remarkable at all, but it was better.
This is where you can see two pictures the colored one is after the black and white is before http://www.amw.com/captures/case.cfm?id=38760

They do have the ability to improve the pictures, but they can't work magic.

As for keeping yourself out of pictures, I have always wondered(and assumed) if there is a way to remove the black bars over your face/other identifying information in a picture that you would add with photoshop/paint etc. If there is a way I think the best bet to combat this would be to black out your face with photoshop etc., print the picture, then scan the printed picture. I believe that this would counter any measures to see your face/identifying information.

That method could also be used to fix the problem of thumbnails, albeit a far more laborious and unnescessary way of doing so.

And yes, I too could not resist the temptation to see some tig ol' bitties:o .

[Hirudinea]

If there is a way I think the best bet to combat this would be to black out your face with photoshop etc., print the picture, then scan the printed picture. I believe that this would counter any measures to see your face/identifying information.


Or you could just view the completly modified picture and do a screen capture of it with another program, that way the screen captured picture would contain only the data that was dispalyed on the screen, then use a secure erase program to get rid of the original picture, clean out all of your hidden files and "hopefully" your secrets are safe. :)

[anonymous411]

"Just like when you shred papers, you can't rely solely on that, you have to use it in addition to fire to ensure destruction."

Have you heard this bit of tradecraft re. the fastest, most efficient way to burn a document?

1. Fold document in half, pleat like an accordion.
2. Place in toilet.
3. Light the creases.

Supposedly it burns very evenly, leaves next to nothing, and generates very little smoke. HTH

[Frunk]

Have you heard this bit of tradecraft re. the fastest, most efficient way to burn a document?


My method involves a large pile of shredded documents and some thermite.

It burns pretty damn evenly. While thermite is not that great for well... anything, lighting huge wads of paper on fire is one of those things it excels at.

KNO3/Sugar works too but it's just not as hot, as in temperature and fun factor.

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For the digital pictures, just select all, copy, new document, paste, save under a new name.

Should get rid of any info attached to the file except the picture.