Re: Is it possible to transfer data by using light
Re: Is it possible to transfer data by using light
- Subject: Re: Is it possible to transfer data by using light
- From: ico <email@hidden>
- Date: Mon, 21 Sep 2015 02:21:44 +0000
After reading all of the replies, no one mentioned how to use iPhone to
detect the light changes (bright and dark) in codes, I just have no clue
how to make it works as long as I remember developers have no right to
access the light sensor, so I guess we have to use camera to achieve this,
but I just don't know how. Can anyone point me to something to read so I
can start digging into this and make the whole thing start to work?
Thank you all.
On Fri, 18 Sep 2015 at 20:38 Michael David Crawford <email@hidden>
wrote:
> Do iOS devices support Trusted Computing in hardware? If so is it
> accessible to userspace apps?
>
> If so, you could store your phones secret in a write-only register.
> For the profoundly paranoid, even the duplication of your storage
> would not yield your phone's secret, The Bad Guy would need your
> personal phone.
>
> Modern Macs - to the best of my knowledge - provide trusted computing
> chips, on can access them from userspace with a modest bit of code.
> Michael David Crawford P.E., Consulting Process Architect
> email@hidden
> http://mike.soggywizard.com/
>
> One Must Not Trifle With Wizards For It Makes Us Soggy And Hard To
> Light.
>
>
> On Fri, Sep 18, 2015 at 3:12 AM, Maxthon Chan <email@hidden> wrote:
> > The "over-the-shoulder" issue can be avoided using what is effectively a
> Diffie-Hellman on top of QR codes. This can be done using front-facing
> cameras on two devices placed face-to-face.
> >
> > Sent from my iPhone
> >
> >> On Sep 18, 2015, at 00:46, Pascal J. Bourguignon <email@hidden>
> wrote:
> >>
> >>
> >>
> >>> On 17/09/15 17:32, Michael David Crawford wrote:
> >>> And what the man said: I myself experience seizures in which I lose
> >>> consciousness for as long as three weeks. Before they were diagnosed
> >>> I would experience seizures while driving my car then suddenly find
> >>> myself in unfamiliar places without any clue how I got there.
> >>>
> >>> I don't know for sure but strongly suspect that modern computer user
> >>> interfaces caused my seizure disorder as well as that of my cousin.
> >>> Seizures are not otherwise found among any of our blood relatives.
> >>
> >> But then if you don't use the whole screen, but only the area that
> >> should be in front of the camera of the superposed phone, then users
> >> shouldn't be subjected to much stroboscopic light.
> >>
> >> Having the objective so close from the light source does not allow
> >> the camera to distinguish pixels; for example, a black to white
> >> transition takes about 1/10 of the height of the camera view.
> >> But this means that you might still able to transmit about ten pixels
> at once,
> >> and you can multiply that by a number of color that you can detect
> reliably
> >> being that out of focus. Basically, I would expect 8 colors to be
> clearly
> >> distinguishable. Actually, probably more colors should be
> distinguishable,
> >> if you can filter out the interferences due to the grid of the camera
> vs.
> >> the grid of the screen. So assume 4 bits for the color, and 9 areas,
> >> that's 36 bit/moment, and you should be able to do 30 moment/second,
> >> for a total of 1080 bit/second. A little less for ECC, about 1 KB/s
> >> is not too bad. It's good enough to transmit a good private key, and
> then
> >> transfer the data thru wifi.
> >>
> >>
> >> Of course, if you move the camera out to focus on the screen, then
> >> you can transmit at a higher speed things like QR codes, but they
> >> could also be seen over the shoulder by high resolution cameras.
> >>
> >> --
> >> __Pascal J. Bourguignon__
> >> http://www.informatimago.com/
> >>
> >> _______________________________________________
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