[PD] high-frequency birdsong

Andy Farnell padawan12 at obiwannabe.co.uk
Mon Jun 6 13:00:13 CEST 2016


Now I remember we used to do this when I was a kid..
It was my first adventure into computer music.
Computers like the TRS80 didnt have soundcards
(or even beepers), but if you put an AM radio nearby it
was possible to make beeps and rhythm patterns by programming,
shorter FOR loops, or less operations in the body... shorter
and higher pitched sounds. It makes perfect sense to reverse
this and figure out the code from the sound.

I think the method still needs a lot of time, Like
collecting IVs for wifi cracking, the information is there,
but dispersed amongst many many samples, so you need to

1) collect a LOT of data
2) analyse it to find how the side channel statistically encodes data/secrets  

In the Genkin paper theres another important point;

Its an interactive attack, relying on "amplifying" side channel effects
adaptively. Thats like being able to poke the bird and make it tweet
(in Jonathan's original analogy). This is quite different from sampling
a signal from a system non-interactively. If you get to ask questions
you can bias answers. So triggering the "bird" to tweet relative to the 
low bandwidth sampling boundary allows us to probe data within the structure
of a signal we could not possibly sample under Nyquist restrictions.
a.



On Sun, Jun 05, 2016 at 08:38:19PM -0400, Matt Barber wrote:
> Figure 6 in the link is measuring up to 20khz over about a half second, and
> showing some kind of step function in the spectrum halfway through. I've no
> idea what they're actually recording.
> 
> On Sun, Jun 5, 2016 at 8:21 PM, Jonathan Wilkes <jancsika at yahoo.com> wrote:
> 
> > I'm trying to wrap my head around this:
> >
> > http://m.cacm.acm.org/magazines/2016/6/202646-physical-key-extraction-attacks-on-pcs/fulltext
> >
> > So to answer the question-- yes, the mic has to respond.  So if the worry
> > is cellphone microphones, I simply don't see how the mic could deliver any
> > useful data whatsoever to the analysis software.
> >
> > -Jonathan
> >
> >
> > On Sunday, June 5, 2016 8:07 PM, Matt Barber <brbrofsvl at gmail.com> wrote:
> >
> >
> > Will your mic respond? Or are the physics immaterial?
> >
> > On Sun, Jun 5, 2016 at 12:47 PM, Jonathan Wilkes via Pd-list <
> > pd-list at lists.iem.at> wrote:
> >
> > Hi list,
> > Suppose a bird sings a song in a frequency range around 1gHz. (Yes, "g"Hz)
> >
> > The song the bird sings is always exactly the same.
> >
> > The bird repeats its song several million times over the course
> > of an hour.
> >
> > If I record at a sampling rate of 44.1kHz below the tree in which the bird
> > is perched,
> > for a duration of one hour, would I be able to recreate the bird's song?
> >
> > -Jonathan
> >
> >
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> >
> >

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