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 <p...@informatimago.com> > 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/ > > _______________________________________________ > > Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) > > Please do not post admin requests or moderator comments to the list. > Contact the moderators at cocoa-dev-admins(at)lists.apple.com > > Help/Unsubscribe/Update your Subscription: > https://lists.apple.com/mailman/options/cocoa-dev/max%40maxchan.info > > This email sent to m...@maxchan.info
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