## Powerline Freq Fingerprinting of Audio

From: andrew cooke <andrew@...>

Date: Wed, 12 Dec 2012 09:29:47 -0300

http://www.bbc.co.uk/news/science-environment-20629671

Very cute idea.  Andrew

### But how easy would it be ...

From: Michiel Buddingh' <michiel@...>

Date: Wed, 12 Dec 2012 17:56:41 +0100

... for a sound technician to ADD a prerecorded, 'genuine' wire noise
to a tampered recording to make it seem genuine?  I'm by no means an
expert on the matter, but it seems like it might be very easy.  And
the police will probably have the expertise to do this.

mvg,
Michiel

### Re: But how easy would it be ...

From: andrew cooke <andrew@...>

Date: Wed, 12 Dec 2012 21:13:20 -0300

True - the use in that article was rather odd and depends on it being an
"unknown" technique.  But just the idea that you can use mains freqeuncy
variations as timestamps is pretty amazing.  I wonder how the accuracy with
which you can identify the date depends on the length of the signal?

Andrew