<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Nov 3, 2016, at 6:26 PM, Mark Saad <<a href="mailto:mark.saad@ymail.com" class="">mark.saad@ymail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="content-type" content="text/html; charset=utf-8" class=""><div dir="auto" class=""><div class="">Ok</div><div class=""> So here is a good read from the land of tinfoil hats and hacking air gapped openbsd laptops via sound.</div></div></div></blockquote><div><br class=""></div><div>I remember when that OpenBSD story came out and was controversial since there was little proof. It was intriguing though, and in theory it seemed like a plausible thing (communicating over ultrasound). I remember reading quite a bit of commentary that your average laptop speakers/microphone didn’t even work beyond the range of human hearing. That intrigued me, so I grabbed some software for my desktop that could generate various simultaneous tones at any given frequency and then grabbed a spectrum analyzer for my laptop. Across the room it was totally possible to send at least 8 simultaneous tones that were not audible, but were completely detectable at the laptop end - meaning I could differentiate between say, 18.5KHz, 19KHz, 19.5KHz, 22KHz, etc. Now it’s a leap to turn that into something that can transfer data at wifi speeds, but 300 baud modem speeds or similar, enough to say, work on a terminal, that seems really doable with not a whole lot of work…</div><div><br class=""></div><div>Anyhow, I find it all intriguing. :)</div><div><br class=""></div><div>Charles</div><br class=""><blockquote type="cite" class=""><div class=""><div dir="auto" class=""><div class=""><a href="http://arstechnica.com/security/2016/11/how-to-block-the-ultrasonic-signals-you-didnt-know-were-tracking-you/" class="">http://arstechnica.com/security/2016/11/how-to-block-the-ultrasonic-signals-you-didnt-know-were-tracking-you/</a></div><div class=""><br class=""></div><div class="">So the tldr parts , ad tracking via ultrasound beacons . Imagine you install the wallmart app to get the 25% off coupon but it's tracking you via ultrasound beacons. </div><div class=""><br class=""></div><div class="">Interesting non the less .</div><div class=""><br class=""><br class="">---<div class="">Mark Saad | <a href="mailto:mark.saad@ymail.com" class="">mark.saad@ymail.com</a></div></div></div>_______________________________________________<br class="">talk mailing list<br class=""><a href="mailto:talk@lists.nycbug.org" class="">talk@lists.nycbug.org</a><br class="">http://lists.nycbug.org/mailman/listinfo/talk</div></blockquote></div><br class=""></body></html>