<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;"><div>On Sep 24, 2014, at 12:55 PM, elijah <<a href="mailto:elijah@riseup.net">elijah@riseup.net</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite">On 09/24/2014 11:08 AM, Tao Effect wrote:<br><br><blockquote type="cite">I've finally taken the time to explain via diagrams and many words how<br>undetected MITM attacks can happen with Certificate Transparency.<br></blockquote><br>It strikes me that you are not allowing for any distinction between a<br>MiTM attack that happens once, and a MiTM attack that is only successful<br>if it can be carried off from the moment a computer first contacts the<br>internet (and carried on forever if the attacker doesn't want to be<br>detected). What scenario do you have in mind where the latter is possible?<br></blockquote><div><br></div>Well, I'm primarily focusing on MITM attacks that happen more than once, and are undetected, but not in the sense that you've presented it (MITM attack 24/7 from beginning of time).<div><br></div><div>A 24/7 MITM attack from birth to death simply goes undetected in all systems, and it's probably impossible to do anything about that.</div><div><br></div><div>However, the issue with CT is as I pointed out several months ago back in May, that detection depends on successful gossip.</div><div><br></div><div>Sure, it's possible, if the gossip succeeds, that proof of failure (not misbehavior) has occurred. The problem here is:</div><div><br></div><div>1. Gossip could be blocked.</div><div>2. If Gossip isn't blocked, and you're able to prove failure... so what? What then? The RFC is rather silent on this.</div><div><br></div><div>The blockchain, on the other hand, doesn't have problem #2.</div><div><br></div><div>Even if MITM suddenly starts blocking all new blocks and only showing blocks it creates, the node has a giant store of accurate data that the MITM cannot modify. Not so with CT.</div><div><br></div><div><blockquote type="cite">Also, if browsers contain auditors, why can't these auditors be<br>pre-seeded with the hash of different logs at the time the browser was<br>compiled?<br></blockquote><br></div><div>Sorry, what is this referring to? The post acknowledges that browsers have public keys of logs.</div><div><br></div><div>Kind regards,</div><div>Greg</div><div><div>
<br class="Apple-interchange-newline"><span style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; display: inline !important; float: none;">--</span><br style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;"><span style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; display: inline !important; float: none;">Please do not email me anything that you are not comfortable also sharing</span><span style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; display: inline !important; float: none;"> with the NSA.</span>
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<br><div><blockquote type="cite"><br><br>-elijah<br><br>_______________________________________________<br>Messaging mailing list<br><a href="mailto:Messaging@moderncrypto.org">Messaging@moderncrypto.org</a><br>https://moderncrypto.org/mailman/listinfo/messaging<br></blockquote></div><br></div></body></html>