Ok, so it's 2am and I can't get to sleep. My mind had started to wander into all kinds of weird and wonderful thought patterns when I stumbled upon a question. Now, this question may seem stupid, pointless, dumb or even obvious to you but to me at this minute I'm rather perplexed. So, here it goes - let's say you want to make a recording but you only have the ability to record audio and not video, you also need to provide a way of authenticating that the recording was made at a specific time. Is there any way of mentioning something in the recording (not the date and time, before you say it lol) that would verify that the recording was made at a specific time and not something that could be known again at a later date for someone to make a recording pretending to be in the past? I hope I explained it as I intended and I look forward to reading your replies.

Uh...how are you recording it? If its with a computer then when you save the file it already will let you know what date you recorded it if you right click the file and go properties and it will say...other then that, I don't quite understand what's so hard about this...you just...say when you recorded it if its analog...

Yeah I know that you could check the date on the file, and you could say the date on the recording. But, if someone else on the other side of the world heard your recording, say on youtube, how could you prove that you recorded the message at the time that you stated?

I dunno...I found this: http://www.springerlink.com/content/u1875124104n733w/

It might not be totally accurate, and it means you could have made the recording at a time in the future but this is probably the best way, and it's pretty easy. turn CNN/BBC/whatever respectable news channel you want on, wait til they show the latest breaking news and put the microphone in the TV's speaker. anyone can easily verify that you couldn't have recorded the news of that day any time earlier.

of course, if you don't have access to media then you can't authenticate it by any accessible means, like some kind of specialized instrument to read natural data which can then be proven to have been recorded on that day and hour.

The only problem with that you could have recorded the news and played that back in the video. I don't think there is a way to record audio and prove it was done at a specific time either present or past...

Has somebody been disagreeing with you about a certain piece of audio and the time when it was recorded? The only real solution is to have it copyrighted...you could also just record the thing and send it to yourself...other than that, no idea...

No it's nothing like that. I just thought it would be a good thought exercise in logic or something if someone could think of an ingenious way to prove something was recorded at a certain time. It's no big deal, just thought it might be something interesting to think about =)

Well I definitely scratched my head over it...

Make a website which generates a unique code randomly for every passing minute and displays it. This is actually not all that difficult to do, maybe someone did it already. Have the computer store every unique code in a large database that is not accessible to anyone but the computer itself. This computer will then be able to tell you the exact time that a certain code was displayed by searching its database.

Mention the code in your audio recording. Searching for this code on the website will forever identify your recording as created at a certain time.

Perfect! At least that's one thing cleared from my mind, thanks =D

Written by jupitreas on 16.03.2010 at 07:30

Make a website which generates a unique code randomly for every passing minute and displays it. This is actually not all that difficult to do, maybe someone did it already. Have the computer store every unique code in a large database that is not accessible to anyone but the computer itself. This computer will then be able to tell you the exact time that a certain code was displayed by searching its database.

Mention the code in your audio recording. Searching for this code on the website will forever identify your recording as created at a certain time.

but then people might argue that you rigged the website into generating a certain code at a certain time which you memorized, or you memorized one from the past.

Written by Valentin B on 16.03.2010 at 18:25

Written by jupitreas on 16.03.2010 at 07:30

Make a website which generates a unique code randomly for every passing minute and displays it. This is actually not all that difficult to do, maybe someone did it already. Have the computer store every unique code in a large database that is not accessible to anyone but the computer itself. This computer will then be able to tell you the exact time that a certain code was displayed by searching its database.

Mention the code in your audio recording. Searching for this code on the website will forever identify your recording as created at a certain time.

but then people might argue that you rigged the website into generating a certain code at a certain time which you memorized, or you memorized one from the past.

see, this is the thing, I am pretty sure with compression and encryption, you can make a code that is not only far too complicated to memorize but also would become unreadable if you make a code up. it could also be in a non-human language, for example a jumbled set of frequencies or something.

anyway, my idea was abstract: the point is that you need an independent source that identifies a certain moment in time with nearly infinite accuracy. i don't think it is possible to include precise and believable information regarding the recording's precise time stamp without an independent, external point of reference. everything else, such as the nature of the compression, encryption, ownership and algorithm of this time-keeping device, is abstract.

Ah, i see now.. well, i guess you could do that, but imo the best way would be to record an exact piece of scientific data which can then be testified as to have occurred at exactly that time(like really technical weather or soil conditions)

I put some thought into this and sadly didn't come up with any way to completely proof the exact time the recording was made. Mainly because any information that is recordable on audio could have been recorded at another time and then added to the recording in question. And appart from quantum cryptography there is any way to proof that a piece of information is truly unique.

My best guess would be to mention a hash value (sort of an one way encryption) of something that is directly linked to a piece of information that is available directly at the time of the recording. To ensure you didn't pre-record it, it is chosen by a third party, be it computer or person without your knowledge as to what it is and out of a pool of information that is infeasible to record. But still people need to trust the third party, this just made someone or something else the one to be trusted instead of yourself.

This still does not work like I imagined, Ill edit this after the knot in my head unwinds.

Written by [user id=104505] on 18.03.2010 at 00:58

I put some thought into this and sadly didn't come up with any way to completely proof the exact time the recording was made. Mainly because any information that is recordable on audio could have been recorded at another time and then added to the recording in question. And appart from quantum cryptography there is any way to proof that a piece of information is truly unique.

My best guess would be to mention a hash value (sort of an one way encryption) of something that is directly linked to a piece of information that is available directly at the time of the recording. To ensure you didn't pre-record it, it is chosen by a third party, be it computer or person without your knowledge as to what it is and out of a pool of information that is infeasible to record. But still people need to trust the third party, this just made someone or something else the one to be trusted instead of yourself.

This still does not work like I imagined, Ill edit this after the knot in my head unwinds.

Thats pretty much what i said.
Also, it is always possible to tell if an audio file has been tampered with, so pasting the hash value into a recording made at another time would be easily recognizable.