...<blockquote type="cite" class="protonmail_quote"><div style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif; font-size: 13px;"><div>Imagine a person with a computer on a canonical hill, with an hyper-wideband SDR radio, spreading out over perhaps 100 MHz in bandwidth.&nbsp; (unused UHF station bands?&nbsp; Military frequency allocations?)&nbsp; I'm thinking of a transmitter of 10-100 watts, which when spread over 100 MHz, is not particularly loud.&nbsp;&nbsp;<br></div></div></blockquote><div><br></div><div>the problem with a singular transmitter is still the trivial location determination - you want to make that last hop hard to find.<br></div><div><br></div><div>previous discussions have suggested MIMO for beam forming / phased array signal emission that lets you do fancy things, like emulate a moving transmitter.&nbsp; if the transmitter appears to be constantly moving, it's a much harder target :)<br></div><div><br></div><div>these systems used to be millions of dollars, and now they are merely thousands. (soon enough only hundreds of $?)<br></div><div><a href="https://lists.cpunks.org/pipermail/cypherpunks/2016-February/027605.html">https://lists.cpunks.org/pipermail/cypherpunks/2016-February/027605.html</a><br></div><div><br></div><div><br></div><blockquote type="cite" class="protonmail_quote"><div style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif; font-size: 13px;"><div>&nbsp;Conceivably,&nbsp; depending on his transmit footprint, 1 million potential listener-computers&nbsp; can hear his signal, also by SDR.&nbsp; He receives data, presumably through VPN or TOR, etc, by means of a packet which is doubly-encrypted:&nbsp; The operator decrypts by using his private key, revealing a still-encrypted packet that he then transmits by ultra-broadband, using a secret provided by the decrypted packet..&nbsp; Anyone who can 'hear' his signal, and who knows the encoding secret, can decrypt the data, but it can only be further decrypted by some further key.&nbsp; So, nobody knows who actually was the intended recipient.<br></div></div></blockquote><div><br></div><div>this is getting into canonical zero knowledge protocols, albeit adapted for wireless mesh networks. if you search the literature for "zero knowledge wireless sensor network" you'll find a long tangle of research to devour in this domain... <br></div><div><br></div><div><br></div><blockquote type="cite" class="protonmail_quote"><div style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif; font-size: 13px;"><div>This amounts to anonymizing "the last 10 miles", making it essentially impossible to learn who is actually receiving this information.<br></div></div></blockquote><div><br></div><div>one benefit of actual broadcast receivers is the ability to distribute a large amount of information to all simultaneously. in some protocols this can be a big advantage. Tor directory information for example, could be broadcast over digital video bands and then partitioning attacks against directory obviated.<br></div><div><br></div><div>bitcoin had discussed doing this for blockchain distribution in Norway, IIRC.<br></div><div><br></div><div><br></div><div>best regards,<br></div><div><br></div>