<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;">On Jan 27, 2015, at 3:23 PM, Ben Laurie <<a href="mailto:benl@google.com">benl@google.com</a>> wrote:<div><blockquote type="cite"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div id=":guw" class="a3s" style="overflow:hidden">Different network designs can also help. If you own the link and both of its ends, it costs you exactly the same to send continuous random bits as to leave the line idle. Any encrypted traffic (assuming an encryptor whose output is indistinguishable from random noise() is then safe from observation. The Hot Line between the US and Moscow was, I believe, designed to work this way. How this extends to a packet-switched network, especially one where you can't trust the switches, is unclear.<br></div></blockquote></div><br>Yeah, but ... who can realistically afford that bandwidth? To every possible recipient? Clearly you have to make a tradeoff.</div></div></blockquote>Just my point. We don't have a theory that would allow us to make the tradeoff in a rational way; we can only guess.</div><div><div> -- Jerry</div><div><br></div></div><br></body></html>