Snowden isn&#x27;t explaining anything here, he&#x27;s just posting a link on Twitter. HN guidelines ask you to &quot;please submit the original source&quot;.<p>The original source is:<p><i>Dirtbox - Devices on Planes Used by Government to Target Cellphones</i> (2014)<p><a href="http:&#x2F;&#x2F;www.securitycurrent.com&#x2F;en&#x2F;writers&#x2F;mark-rasch&#x2F;dirtbox-devices-used-to-target-cellphones" rel="nofollow">http:&#x2F;&#x2F;www.securitycurrent.com&#x2F;en&#x2F;writers&#x2F;mark-rasch&#x2F;dirtbox...</a>