Telling the date and time of a recording by listening to the sound?

[IanB]

OK, I'm sure many people will have seen Tom's video on this, but if you haven't, would you care to guess how? It's not something that would have occurred to me.

In short: Given an audio recording containing ambient sound, then by doing signal processing on it, it may be possible to locate the exact date and time of the recording.

Could you guess, if you didn't know the answer?

[MK14]

I haven't seen the video.

I think I can guess how it works.

Do you want me to say, or leave the thread without answers, for others to say if they get it or not ?

I could of course be mistaken.

[Cerebus]

If this is the technique I think it is, which I read about a few months back, I'd say that it's not what I'd call "immediately obvious". It's one of those things that when you hear it you think "Really? I can see how it could work, but I'm surprised to find that it actually does work.".

[IanB]

I guess if anyone doesn't want to spoil it by posting their guess, then you could message me and I'll confirm it here?

[MK14]

I guess if anyone doesn't want to spoil it by posting their guess, then you could message me and I'll confirm it here?

I've checked by watching part of the video. I was WRONG.

It wasn't obvious to me, actually I would be impressed with anyone, who can solve it themselves, without cheating.

[Cerebus]

Well in my case it's not so much a guess as prior knowledge, so I've no grand insight to lay a claim to. Unfortunately white text is merely hard to read on here rather than an effective ersatz way of concealing a 'spolier'.

[IanB]

madires sent me a message with the correct answer, but apparently this was from prior knowledge

[madires]

There's a method known for several years. And it can even give you a rough idea of the location.

[tom66]

I think I know:
fd91337f6434fa47a2ff6764f83b7f3ef52f2eec0aa3d93d6cc3adfecc0e89f1

[Cerebus]

There's a method known for several years. And it can even give you a rough idea of the location.

Assuming we're talking about the same technique one needs historical data to be able to do the timestamping/locating.

[Cerebus]

I think I know:
fd91337f6434fa47a2ff6764f83b7f3ef52f2eec0aa3d93d6cc3adfecc0e89f1

What are you claiming? The answer, or how to produce an arbitrary hash collision on demand? 

[IanB]

I think I know:
fd91337f6434fa47a2ff6764f83b7f3ef52f2eec0aa3d93d6cc3adfecc0e89f1

Yes, that is it.

[tom66]

I think I know:
fd91337f6434fa47a2ff6764f83b7f3ef52f2eec0aa3d93d6cc3adfecc0e89f1

What are you claiming? The answer, or how to produce an arbitrary hash collision on demand? 

Hey, if you manage to trivially hash-collide this algorithm, then you'll be a very very wealthy individual indeed.

[IanB]

I think I know:
fd91337f6434fa47a2ff6764f83b7f3ef52f2eec0aa3d93d6cc3adfecc0e89f1

And by the way, posting an encrypted answer is definitely one way to conceal it 

[madires]

Assuming we're talking about the same technique one needs historical data to be able to do the timestamping/locating.

Yep! Some nerds are running probes collecting and streaming that data for fun. So it's not hard to get everything you need. I wouldn't be surprised if some three letter agencies do that already for decades.

[Cerebus]

Yep! Some nerds are running probes collecting and streaming that data for fun. So it's not hard to get everything you need. I wouldn't be surprised if some three letter agencies do that already for decades.

Yeah, if they weren't doing it before 2015 (when the paper we're both thinking of was published) I can bet every embassy in the world got a package from the NSA or their national equivalent with a label saying "Plug this into the wall and connect it the the internet."

[PA0PBZ]

Yep! Some nerds are running probes collecting and streaming that data for fun. So it's not hard to get everything you need. I wouldn't be surprised if some three letter agencies do that already for decades.

Yeah, if they weren't doing it before 2015 (when the paper we're both thinking of was published) I can bet every embassy in the world got a package from the NSA or their national equivalent with a label saying "Plug this into the wall and connect it the the internet."

Right, I was thinking of a solution to the problem and first thought it was a bit far-fetched but now I know I found it 

[PlainName]

I'm sure many people will have seen Tom's video on this

Who is 'Tom' and where might this video be?

[IanB]

Who is 'Tom' and where might this video be?

Tom Scott. YouTube.

[PlainName]

Thanks.

Er, if the chappy is popular, presumably he has many videos. Any reason you want to make it hard to find the actual video?

Oh, sod it. Just tell us how it''s done - no-one this far into the thread won't have gone to look if they could and wanted to.

[MK14]

Thanks.

Er, if the chappy is popular, presumably he has many videos. Any reason you want to make it hard to find the actual video?

Oh, sod it. Just tell us how it''s done - no-one this far into the thread won't have gone to look if they could and wanted to.

Code: [Select]

https://www.youtube.com/watch?v=e0elNU0iOMY

[PlainName]

Thank you

[langwadt]

haven't watched the video yet, but I'd guess variations in the mains frequency. I believe that is also used to check if a recording might have been altered by removing or adding parts   

[IanB]

Thanks.

Er, if the chappy is popular, presumably he has many videos. Any reason you want to make it hard to find the actual video?

Oh, sod it. Just tell us how it''s done - no-one this far into the thread won't have gone to look if they could and wanted to.

I'm sorry, but nobody here lacks the ability to go to YouTube and type "Tom Scott" into the search box. It's not "hard". It's trivial. It took you longer to write that post than to actually go and do it.

[PlainName]

It took you longer to write that post than to actually go and do it.

It didn't actually. So, I got to some Tom Scott youtube page. Will the video be obvious? Before I got there I won't know, will I, and I might not even find the right one if the titles are iffy or it's buried deep. Don't forget, I have no idea who Tom Scott is, nor what his videos look like, how they are titled, nothing.

Or, since YOU want us to comment on it, you could've just pasted the URL faster than I could've thought 'who the fuck is...'

Pro tip: if you want up to date stuff, don't bother with Tom:

(obscured in case anyone still hasn't sussed it since 2014)
https://bit.ly/3H4yOJv