gv250 and video authentication

[pcmeister 0]

I have never used the GV software, and have a few questions before I get the GV250. Can someone please tell me. Basically, what I want to do boils down to this-

 

I want to record about 8 continous hours of video footage using the digital watermark feature, which I assume will make the footage court admissible. I want to show that the video was recorded uninterrupted for the full 8 hours and could not have been tampered by anyone, including me. Is this do-able with geovision?

 

Also, looking at some screenshots of the program, I notice the timeline is broken into individual parts that are about 5 minutes apart. Do these individual parts correspond to small video files on the hard drive that are individually watermarked? I'm trying to understand how all this works. Thanks.

[kensplace 0]

Geo has a 5 min size limit on the record files, so they dont get too large.

Watermarking is per file, and automatic (if turned on).

 

As far as tampering goes, watermarking, in fact pretty much any security feature is fairly pointless if the holder/provider of the evidence wishes to tamper with the evidence - at least thats what I could argue in a court.

[pcmeister 0]

I assumed the whole point of watermarking is to show that the video could not have been tampered by ANYONE, including the operator. But that is not necessarily so?

 

Regarding the 5 min files, I assume they are assembled together for exportiing and the final video will be basically seamless and have no missing video (like in seconds) whatsoever? And the watermarking process is applied to the individual files as they are recorded, and it survives the export process?

 

 

Geo has a 5 min size limit on the record files, so they dont get too large.

Watermarking is per file, and automatic (if turned on).

 

As far as tampering goes, watermarking, in fact pretty much any security feature is fairly pointless if the holder/provider of the evidence wishes to tamper with the evidence - at least thats what I could argue in a court.

[kensplace 0]

Never actually exported anything yet on my geo system, so not sure!

 

If no one chimes in I will try later (probably tommorow) and get back with results.

 

As far as watermarking goes, firstly the evidence could be faked and genuinely watermarked (if that makes sense) then substituted for the real footage, OR if the stakes are high enough, you need to remember that ANYTHING done by a computer or by a dvr, is done by software.

 

Software can be disassembled, and reverse engineered - so if the stakes were high enough (say a large robbery or murder) and technical skills where available (or hired) then evidence could be altered before being produced.

 

There are ways to get around it, some easy, some hard (very) but it boils down to trust at the end of the day, if the source of the evidence is trusted, then trust the evidence.

 

If not - then a good lawyer (if such a thing exists) *should* be able to get around watermarking in most cases (PS IM NOT A LAWYER)

[pcmeister 0]

I greatly appreciate your reply.

As ridiculous as this might be, can I get your take on this scenario:

 

Let's say I want to provide proof showing that someone has been in a room for an extended period of time and at a time that no one is supposed to be in the room, and this person exits the room through a door at a fairly predictable time, after being in the room for about 12 hours. I want to provide footage, like 8 hours worth, of the door not moving until the time the person exits, thereby proving the person was in there all that time.

 

To establish the real correct time in the footage, I could begin recording with a time/date overlay, and then hold the camera in my hand, pointing it at a laptop screen with windows xp on it, and then do an internet time update a couple of times to demonstrate that the time/date shown on the laptop screen is indeed the correct time, and it matches the time shown on the overlay. I would also show that the time zone is correct on the laptop's screen. Then in one fluid motion, I would move the camera slowly away from the laptop screen to the position it will assume for the next several hours, pointing at the door. The camera will stay focused on the door with the time/date overlay ticking away for the next 8 hours until the person can be seen exiting the door. Then, right afterwards, I would export the footage and hand it over to another person for safekeeping, and to show that it could not have been tampered by me, the operator in that short period of time. The watermark feature will of course been turned on from the start.

 

Could this method hold up to a lawyer's scrutiny, or is this a laughable idea?

 

 

Never actually exported anything yet on my geo system, so not sure!

 

If no one chimes in I will try later (probably tommorow) and get back with results.

 

As far as watermarking goes, firstly the evidence could be faked and genuinely watermarked (if that makes sense) then substituted for the real footage, OR if the stakes are high enough, you need to remember that ANYTHING done by a computer or by a dvr, is done by software.

 

Software can be disassembled, and reverse engineered - so if the stakes were high enough (say a large robbery or murder) and technical skills where available (or hired) then evidence could be altered before being produced.

 

There are ways to get around it, some easy, some hard (very) but it boils down to trust at the end of the day, if the source of the evidence is trusted, then trust the evidence.

 

If not - then a good lawyer (if such a thing exists) *should* be able to get around watermarking in most cases (PS IM NOT A LAWYER)

[kensplace 0]

I think most of the time, if footage is available, that is usually all that is needed, but if it came down to a legal battle, then things could be argued...

 

In a worst case scenario, which is unlikely, it could be argued that you faked the dns on your portable and went to a 'fake' time site, showing the time you wanted, plus the time / date overlay was pre-programmed with the time you wanted....

 

You could always have a reliable witness (police officer or similar professional would be great....) to swear you set up the camera correctly and the time/date is correct and that you had no access to the footage to tamper with it.

 

Like I say though, usually you wont get a problem like that, but if you expect one, cover your back fully

 

If possible, have stick a TV in the room that the person is not meant to be in, chances are they will watch it. If they are in the room watching the tv, and on camera it shows them AND the TV in the same shot, you can prove that the time/date is correct by what was shown on the tv.

(make sure the witness can testify the tv was not connected to a video recorder or anything that could play pre-recorded stuff)

[phred 0]

There are such things as tamper proof clocks.

Basically a GPS clock that picks up time from a satellite and has no

controls for altering the time. They are often used in TV/ radio studios.

 

Getting one of these in the shot would be pretty difficult to fake.

[CollinR 0]

There are such things as tamper proof clocks.

Basically a GPS clock that picks up time from a satellite and has no

controls for altering the time. They are often used in TV/ radio studios.

 

Getting one of these in the shot would be pretty difficult to fake.

 

Not as long as it's taking place indoors... Not much different from Ken's modified DNS example.

 

If someone is knowledgable enough just about anything can be faked/bypassed.

 

 

 

Sidenote on Ken's DNS example! I actually did this and it worked PERFECTLY. When I proposed to my wife I rerouted a page from Geocaching.com to my local apache server. It was classic I couldn't believe she bought into it. Sure enough she did, we found the bogus cache and in it the engaugment ring. I was not going to be leaving the ring in a real "live" cache, this worked perfectly.

[pcmeister 0]

LOL. I'm not sure if this will do it, but how about running a network analyzer program's (like wireshark or ethereal) activity screen in a window that will show detailed network activity while doing the time check.

 

Sidenote on Ken's DNS example! I actually did this and it worked PERFECTLY. When I proposed to my wife I rerouted a page from Geocaching. com to my local apache server. It was classic I couldn't believe she bought into it. Sure enough she did, we found the bogus cache and in it the engaugment ring. I was not going to be leaving the ring in a real "live" cache, this worked perfectly.

[phred 0]

You could still be running a screen capture of the whole thing rather than

doing it live.

 

Perhaps you could start recording outside and capture some video of

shadow positions, that would indicate the position of the sun and give a fix for the time. Then keep shooting to keep the time code continuous.

[pcmeister 0]

It would be great if there existed some robust surveillance software that would force the user to connect to the company's servers for time/date setting according to the user's timezone determined by IP number (that is, the software wouldn't permit recording unless this time syncing is done at the beginning of the session), and then allow a multiple-hour single video file to be recorded, watermarked.

 

You could still be running a screen capture of the whole thing rather than

doing it live.

 

Perhaps you could start recording outside and capture some video of

shadow positions, that would indicate the position of the sun and give a fix for the time. Then keep shooting to keep the time code continuous.

[pcmeister 0]

I might be better off replacing the surveillance setup with a single reliable witness; the problem is the person must sit still for many hours without falling asleep LOL.

 

I think most of the time, if footage is available, that is usually all that is needed, but if it came down to a legal battle, then things could be argued...

 

In a worst case scenario, which is unlikely, it could be argued that you faked the dns on your portable and went to a 'fake' time site, showing the time you wanted, plus the time / date overlay was pre-programmed with the time you wanted....

 

You could always have a reliable witness (police officer or similar professional would be great....) to swear you set up the camera correctly and the time/date is correct and that you had no access to the footage to tamper with it.

 

Like I say though, usually you wont get a problem like that, but if you expect one, cover your back fully

 

If possible, have stick a TV in the room that the person is not meant to be in, chances are they will watch it. If they are in the room watching the tv, and on camera it shows them AND the TV in the same shot, you can prove that the time/date is correct by what was shown on the tv.

(make sure the witness can testify the tv was not connected to a video recorder or anything that could play pre-recorded stuff)

[phred 0]

Pcmeister

 

I think you have raised an important point. If the time code is such an

important aspect of recordings for evidential purposes, why has more not

been done to ensure its veracity ?

 

 

Your IP solution sounds like a sensible idea – I hope some manufacturers

read this and realise the gaping security hole that currently exists -

preferably before some sharp lawyer does!