Online backup services, EXIF and validation

Tamron SP AF 28-75mm f/2.8 XR Di for Canon

08/29/2007 02:43:04 PM · #1

I currently use an online back-up service for my home computer (piggyback account from my office computer) and was wondering: Would an original photo restored from this service still be usable as an original for validation? As in, would the EXIF still be intact and show the photo had not been altered? I know they encrypt the files before they go over the net to the off-site storage, but no idea what method they use. I have restored a photo file from them and with the EXIF reader I have all looks good. But I know the SC has 'secret' methods and tools they use. Has anyone had experience with or knowledge of this?

Thanks in advance.

Any SC who read this: can I restore a file and have it checked as if it was for validation to see if there would be a problem? If yes, who to/how to achieve this? This wouldn't be a challenge entry, just any photo I pull off the back-up drive.

Message edited by author 2007-08-29 14:44:51.

AJSullivan

08/29/2007 02:50:16 PM · #2

I honestly don't see why not, if its literally taking a copy of your hard drive and just storing it somewhere, then there is no reason it would alter the .exif data.

I mean its really the equivalent of emailing a file, burning a file to a cd, or other sort of back up.

Message edited by author 2007-08-29 14:51:29.

Canon EOS-20D

08/29/2007 02:51:22 PM · #3

Originally posted by CEJ:

Any SC who read this: can I restore a file and have it checked as if it was for validation to see if there would be a problem? If yes, who to/how to achieve this? This wouldn't be a challenge entry, just any photo I pull off the back-up drive.

Yes, go ahead and submit a ticket and attach the file. That's really the only way we can answer the question. To my knowledge, we haven't dealt with this before.

Canon RF 24-70mm f/2.8 L IS

08/29/2007 02:55:40 PM · #4

Originally posted by ajdelaware:

if its literally taking a copy of your hard drive and just storing it somewhere

They encrypt/decrypt the file when it passes from my system to theirs and back. Hence the question. The image has not been altered, but the file has in a way.

MK - Ok, will do tonight sometime. I did not know if it was OK to just submit a photo for this purpose without some discussion beforehand. Thanks.

Oh and for the record, I don't anticipate this ever happening, but then you never anticipate a hard drive crash either.

Message edited by author 2007-08-29 14:57:08.

klkitchens

Pentax K-1

Pentax FA 50mm f/1.4 AF

08/29/2007 03:01:29 PM · #5

it should be like any file transfer, the file is not really encrypted -- a copy is.

Our computers use encryption ALL THE TIME for downloading from the internet, via USB, etc. -- nothing really "moves" either. It just receives a signal that says "Hey, this bit is on, this bit is off, this bit is off, etc." The receiving computer gets that message and starts storing bit on, bit off, bit off... based on the message.

So I doubt very seriously the encrypt/decrypt actually "changes" the file itself.

AJSullivan

08/29/2007 03:05:38 PM · #6

Yeah, if data encryption changes the integrity of the document, then whats the point anyway? That would cause more issues then its worth then.

kirbic

Canon EOS R5

08/29/2007 03:19:41 PM · #7

The encryption process is a little like lossless compression. It *does* change the content of the file, but is reversible. A file that's been encrypted and decrypted should be the same as the original. It certainly won't change the EXIF, however it's possible that the process will reset the file modification date. As mk stated, the safest way is to submit a ticket with a sample file.

levyj413

Apple iPhone 15 Pro Max

Tamron SP AF 17-50mm f/2.8 Di II LD Aspherical (IF) for Nikon

08/29/2007 04:45:17 PM · #8

Originally posted by kirbic:

It certainly won't change the EXIF, however it's possible that the process will reset the file modification date.

Right, which raises the question: is file modification date relevant to SC reviews? I noticed that the file date on some NEF files showed the day I copied them to the computer, for example. I just assumed the SC looked at the EXIF only, which of course doesn't change.

So - do ya?

AJSullivan

08/29/2007 04:56:03 PM · #9

Well if you emailed them the file and they downloaded it to their computer, then the file modification date is going to change then anyway. Its not like the same date carries over from your computer to theirs, unless you put it on a cd and even then I think it records the write date of that cd.

kirbic

Canon EOS R5

Canon RF 24-70mm f/2.8 L IS

08/29/2007 05:05:06 PM · #10

Originally posted by levyj413:

[...is file modification date relevant to SC reviews?

We have not found the file modification date to be any kind of reliable indicator as to whether the file is "original." Too many things can change it. We use (multiple) other means for determining whether a file was altered.

08/29/2007 09:42:42 PM · #11

OK, I just submitted two tickets. The first has the RESTORED file attached and the second has the UNRESTORED/ORIGINAL file attached. I look forward to the results. Thanks kirbic and MK for the interest.

EDIT: Just realized a potential mistake while out so the dog could do his business. I renamed the file. If it helps, it was taken on July 4, 2007.

Message edited by author 2007-08-29 21:58:47.