Recording videos that can´t be edited, only read and exported/copied

[sta]

Hello,

I need to record video files, that can't be edited or are authenticated, immediately after being created, not even by me. The videos need to have a good audio quality.

I am not a tech expert or newbie. I am looking for someone or contact of experts that can do one of the following (payed service):

1. Install/replace the audio codec on a surveillance DVR with an audio codec with better quality: pcm, 16 bits, 44kz, 500kb/s to 700kb/s. I have the firmware upgrade file.

2. Run a laptop with Linux installed, to act like a DVR. Install a software that only records video. Block everything even internet connection, remove every app/service, to prevent the recorded videos from being edited, even from me. The videos need to be readable.

3. Any other alternative.

Thank you

 

[MikeWalsh]

In other words, you want a stripped-down, minimal Linux install that will act like a DVR.....and nothing else.

At a guess, you'll want summat like Xeoma:-

Xeoma – best video surveillance software – Felenasoft

Xeoma is free video surveillance software with 100+ video analytics and AI-powered features like faces and license plate recognition, detection of abandoned objects and many other. Works on all major operating systems (Windows, Linux/ARM, Mac, Android) with iOS and Android client apps and...

felenasoft.com

.....for the DVR stuff. As for making stuff so it's "read-only", the others here can help with that better than I can....

It's not impossible. It's "do-able"..!


Mike.

 

[sta]

Hello,
Thank you for your reply.

The DVR encrypts the hard drive, to prevent the files from being directly read and edited with other computers, even with Linux installed. To prevent video tampering. The aim is to use the videos as judicial evidence.

Is it possible to install Linux on a laptop with such feature?

Thank you

 

[KGIII]

It's rather impossible to make a file that can't be edited even by you. Any protection you put in place you could undo. Storing it encrypted would mean it has to be decrypted to access it. You could then (rather easily) change the permissions.

Now, what you can do is record the video and capture the hash values (checksum) and store those in a couple of places. Then, you check the hash to verify that it hasn't been tampered with.

I do not know about your judicial system, but here in the US they'd tear into anything like that, calling the credibility an issue. So, that's why you store checksums. Then math shows beyond reasonable doubt that the video hasn't been tampered with.

Anything can be edited. You can use a capture card while the video streams and make your own recording, edit that, and put it where the original file was. You can even set the access and modification times stored in the metadata.

But, you're not going to be able to (trivially) mess with the hash values.

 

[sta]

Hello,

Thank you for your reply.

Can hash values be generated by any recording software? How are they captured, during the recording process or after the file is created and stored on the disk?

If the checksum is created after the file was created and stored on the disk, how is it possible to prove that the file is original? In other words, how can one know that the file was only recorded and not edited?

I can create a checksum of an edited file and say it is original, am I correct?

How can hash values (checksums) be automatically captured while and only when the file is being recorded, and later automatically stored when the file is being saved to the disk? Do you know any video recording software with such feature?

If checksums are supported by the video recording software, how do I know they are not being generated for a file that is being edited?

Is it possible to use a script, for example in OBS, for offline recording?

Thank you

 

[KGIII]

The sum isn't so much as it's created, as it is what it is. Let's see if this explains it better than I can:

Using SHA Checksums

You get the value as soon as you've stopped recording. You preserve that value, preferably in duplicate I would imagine.

They're values learned as soon as you stop recording. You don't really make them, they're just the results of the file being the file that it is. If the file is edited, even by a byte, the value will be different.

As this is a legal thing, you're gonna want to talk with lawyers and computer security specialists - more than just some folks on a forum. I'm just giving you potential ideas that you can take to them and ask if that's the right way to implement such a system.

 

[sta]

Thank you for your advice

 

[KGIII]

Thank you for your advice

No problem. I did some searching earlier and it looks like checksums are generally considered valid proof in at least some legal systems. So, there's something to consider.

There's really no such thing as a file that can't be edited, given enough effort. But, you can mathematically prove that a file hasn't been tampered with (for some definition of proof). Of course, there's still the chain of custody for the hash. You'll likely need that in duplicate and with some sort of witness to the fact.

The hashes can be stored on read-only memory, like a write-once DVD (not a DVD-RW), among other things. You'd want separate instances, as someone could just replace the whole DVD in that scenario.

It's a pretty tricky concept. I'm sure there are some methods that the courts accept locally. A lawyer in your jurisdiction would definitely be able to drum up some information about this.