Hashes and other hazards:

Camera makers understand that their cameras have to work with other editing
tools.  Making a change that encrypts the image is not going to fly very
well.  A single bit flip results in a corrupt file.
A hash value on part of the image could be useful for verifying that the
image  hasn't been modified since being downloaded from the camera.  This
would mean however that any camera maker has to come up with a unique way
to hasn their image.  Otherwise, the user only has to recalculate the hash.

Yes:  There needs to be extensive checking with each firmware version to
check that things don't break.  At this point you need to decide how
paranoid to be:

* I will keep my raw images sacrosanct.  Keep them in triplicate:  One on
my computer, one in the cloud, one in a disk in a fire/water proof data
safe in the garage, one on a periodic backup disk stored at my dad's farm
* I will keep the original images in a separate folder, process them once
to give each one a unique ID.
* I will keep original images in a separated folder, and add as much
metadata as the file format supports to my images, figuring that images
lost to corruption is a lower risk than images lost to bad indexing.  At
some point when I need disk space I discard the originals.
* I will just keep my dozen memory cards in a box in my desk, figuring that
metadata induced corruption will show up before I start to recycle the
cards.
* I'll download the images, reformat the card, and when a problem shows up,
go out and reshoot the event.

I'm probably about a #3 or #4 right now.

Benefits:  I have been bitten by the "I can't find the original" of this
image several times, and I only have about 40,000 images.  In some cases I
had to use a similar image.  In a few I've had to reshoot an image.
 I have only once had a loss of images cause by a software malfunction --
and that was Nikon's own software.





Regards

Sherwood



On Wed, 29 Jan 2020 at 13:00, <[email protected]> wrote:

> What would you do when camera makers decided to store a cryptographic
> hash or even a signature created over the image and other metadata?
> You'd invalidate the whole image.
>
> I'm not saying they do, but one day they might.  Would be a nice
> feature to certify to some extent how the image was taken.
>
> If you want to bet your images on the belief that some spare time
> programmers can always keep up with each and every turn
> multi-million-dollar companies do on their undocumented, proprietary
> formats, be my guest.  And bring popcorn.
>
> I see no benefit that would outweigh the risk.
>
>
> --
> Dr. Stefan Klinger -- Informatiker, Mathematiker              o/X
> https://stefan-klinger.de                                     /\/
> I prefer receiving plain text messages, not exceeding 32kB.     \
>
> ____________________________________________________________________________
> darktable user mailing list
> to unsubscribe send a mail to
> [email protected]
>
>

____________________________________________________________________________
darktable user mailing list
to unsubscribe send a mail to [email protected]

Reply via email to