Telling the date and time of a recording by listening to the sound? - Page 1
Forum section: electronics / general

author: IanB
author_rank: Super Contributor
timestamp: December 20, 2021, 06:05:22 pm
content: 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?

author: MK14
author_rank: Super Contributor
timestamp: December 20, 2021, 06:11:54 pm
content: 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.

author: Cerebus
author_rank: Super Contributor
timestamp: December 20, 2021, 06:21:33 pm
content: 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 itcouldwork, but I'm surprised to find that it actuallydoeswork.".

author: IanB
author_rank: Super Contributor
timestamp: December 20, 2021, 06:28:28 pm
content: 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?

author: MK14
author_rank: Super Contributor
timestamp: December 20, 2021, 06:30:02 pm
content: Quote from: IanB on December 20, 2021, 06:28:28 pmI'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.

author: Cerebus
author_rank: Super Contributor
timestamp: December 20, 2021, 06:33:32 pm
content: 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. Unfortunatelywhite textis merely hard to read on here rather than an effective ersatz way of concealing a 'spolier'.

author: IanB
author_rank: Super Contributor
timestamp: December 20, 2021, 06:39:13 pm
content: madires sent me a message with the correct answer, but apparently this was from prior knowledge

author: madires
author_rank: Super Contributor
timestamp: December 20, 2021, 06:41:43 pm
content: There's a method known for several years. And it can even give you a rough idea of the location.

author: tom66
author_rank: Super Contributor
timestamp: December 20, 2021, 06:43:24 pm
content: I think I know:fd91337f6434fa47a2ff6764f83b7f3ef52f2eec0aa3d93d6cc3adfecc0e89f1

author: Cerebus
author_rank: Super Contributor
timestamp: December 20, 2021, 06:46:52 pm
content: Quote from: madires on December 20, 2021, 06:41:43 pmAssuming we're talking about the same technique one needs historical data to be able to do the timestamping/locating.

author: Cerebus
author_rank: Super Contributor
timestamp: December 20, 2021, 06:48:07 pm
content: Quote from: tom66 on December 20, 2021, 06:43:24 pmWhat are you claiming? The answer, or how to produce an arbitrary hash collision on demand?

author: IanB
author_rank: Super Contributor
timestamp: December 20, 2021, 06:49:01 pm
content: Quote from: tom66 on December 20, 2021, 06:43:24 pmYes, that is it.

author: tom66
author_rank: Super Contributor
timestamp: December 20, 2021, 06:52:31 pm
content: Quote from: Cerebus on December 20, 2021, 06:48:07 pmHey, if you manage to trivially hash-collide this algorithm, then you'll be a very very wealthy individual indeed.

author: IanB
author_rank: Super Contributor
timestamp: December 20, 2021, 06:52:44 pm
content: Quote from: tom66 on December 20, 2021, 06:43:24 pmAnd by the way, posting an encrypted answer is definitely one way to conceal it

author: madires
author_rank: Super Contributor
timestamp: December 20, 2021, 06:59:39 pm
content: Quote from: Cerebus on December 20, 2021, 06:46:52 pmYep! 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.

author: Cerebus
author_rank: Super Contributor
timestamp: December 20, 2021, 07:23:09 pm
content: Quote from: madires on December 20, 2021, 06:59:39 pmYeah, 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."

author: PA0PBZ
author_rank: Super Contributor
timestamp: December 20, 2021, 07:29:14 pm
content: Quote from: Cerebus on December 20, 2021, 07:23:09 pmRight, 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

author: PlainName
author_rank: Super Contributor
timestamp: December 20, 2021, 08:11:15 pm
content: QuoteWho is 'Tom' and where might this video be?

author: IanB
author_rank: Super Contributor
timestamp: December 20, 2021, 08:15:13 pm
content: Quote from: dunkemhigh on December 20, 2021, 08:11:15 pmTom Scott. YouTube.

author: PlainName
author_rank: Super Contributor
timestamp: December 20, 2021, 08:57:17 pm
content: 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.

author: MK14
author_rank: Super Contributor
timestamp: December 20, 2021, 08:58:50 pm
content: Quote from: dunkemhigh on December 20, 2021, 08:57:17 pmCode:https://www.youtube.com/watch?v=e0elNU0iOMY

author: PlainName
author_rank: Super Contributor
timestamp: December 20, 2021, 09:06:04 pm
content: Thank you

author: langwadt
author_rank: Super Contributor
timestamp: December 20, 2021, 09:18:44 pm
content: 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

author: IanB
author_rank: Super Contributor
timestamp: December 20, 2021, 09:25:17 pm
content: Quote from: dunkemhigh on December 20, 2021, 08:57:17 pmI'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.

author: PlainName
author_rank: Super Contributor
timestamp: December 20, 2021, 09:35:53 pm
content: QuoteIt 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

author: IanB
author_rank: Super Contributor
timestamp: December 20, 2021, 09:48:39 pm
content: The claim was about time and date, rather than geographical location.Tom gave a researcher some sample material to test, and they were able to get an accurate result in some cases.It may have been first reported a few years back, but not everyone has come across it.