Luminous Landscape Forum

Raw & Post Processing, Printing => Digital Image Processing => Topic started by: jolson12 on January 25, 2007, 10:11:05 am

Title: Protecting Metadata
Post by: jolson12 on January 25, 2007, 10:11:05 am
Does anyone know of a way to protect metadata from edits?

What I mean is, to keep someone from changing the original metadata information of a image file to their own information (copyright.....).



Jim Olson
Title: Protecting Metadata
Post by: Jonathan Wienke on January 25, 2007, 10:58:30 am
Not really. Files are editable. The best thing to do is not give out the full-resolution file to anyone you don't trust. If there is a dispute of ownership, if you can produce a full-resolution image and the other party cannot, you have a lot better standing. If image theft is an issue, watermark.
Title: Protecting Metadata
Post by: Tim Gray on January 25, 2007, 11:32:00 am
I suppose you could apply some kind of public/private key encryption.
Title: Protecting Metadata
Post by: Jonathan Wienke on January 25, 2007, 11:42:25 am
A digital signiture can prove the file was altered, but will not prevent alteration.
Title: Protecting Metadata
Post by: john beardsworth on January 25, 2007, 11:57:45 am
Quote
I suppose you could apply some kind of public/private key encryption.
[a href=\"index.php?act=findpost&pid=97497\"][{POST_SNAPBACK}][/a]
And how certain can you ever be that you, the rightful owner, will be able to change metadata in the future with your chosen software on your preferred OS? Software comes, software goes. JW's spot on here.

John
Title: Protecting Metadata
Post by: Tim Gray on January 25, 2007, 12:45:15 pm
Quote
And how certain can you ever be that you, the rightful owner, will be able to change metadata in the future with your chosen software on your preferred OS? Software comes, software goes. JW's spot on here.

John
[a href=\"index.php?act=findpost&pid=97501\"][{POST_SNAPBACK}][/a]

PKI is a standard with Fortune 500 clout.  If it's "not available in the future" then there are bigger problems to worry about.  Also it does prevent changes to the original content - just try making changes to a secure PDF document.  

I guess the "gotcha" is the use of "original" in the paragraphy above.  Obviously there's no way of protecting images displayed on the internet - regardless of what protection is put in place to preserve the exif  - you just grab the displayed pixels.  So in the long run, if there's a way to display the image, there will always be ways to copy it and leave the encrypted content behind.  Same problem faced by RIAA et. al.

My recollection is that Canon had some kind of (hardware?) that plugged in to provide authentication that the content of a digital file hadn't been altered to support the presentation of that evidence in court.   Which goes to Jonothan's point that you can prove an alternation, but not prevent it.  Wouldn't being able to prove the alteration be sufficient?
Title: Protecting Metadata
Post by: Jonathan Wienke on January 25, 2007, 12:56:17 pm
Quote
My recollection is that Canon had some kind of (hardware?) that plugged in to provide authentication that the content of a digital file hadn't been altered to support the presentation of that evidence in court.   Which goes to Jonothan's point that you can prove an alternation, but not prevent it.  Wouldn't being able to prove the alteration be sufficient?

Canon Data Verification Kit (http://web.canon.jp/Imaging/eos1dsm2/html/17_data.html)

It depends. If you're trying to stop someone from taking a headshot you took and putting in on a porn-star's body and posting it on the net, or generally misusing a photo you posted on the net, good luck. A digital signature won't help you at all. But if someone is suing you because they claim you retouched a photo to defame them and you didn't alter the photo, a signature could be quite handy.