tor-webwml.git

@@ -1091,6 +1091,23 @@ tradeoff.</li>

 <li>It's not that hard to DoS Tor relays or directory authorities. Are client

 puzzles the right answer? What other practical approaches are there? Bonus

 if they're backward-compatible with the current Tor protocol.</li>

+<li>Programs like <a

+href="https://torbutton.torproject.org/dev/">Torbutton</a> aim to hide

+your browser's UserAgent string by replacing it with a uniform answer for

+every Tor user. That way the attacker can't splinter Tor's anonymity set

+by looking at that header. It tries to pick a string that is commonly used

+by non-Tor users too, so it doesn't stand out. Question one: how badly

+do we hurt ourselves by periodically updating the version of Firefox

+that Torbutton claims to be? If we update it too often, we splinter the

+anonymity sets ourselves. If we don't update it often enough, then all the

+Tor users stand out because they claim to be running a quite old version

+of Firefox. The answer here probably depends on the Firefox versions seen

+in the wild. Question two: periodically people ask us to cycle through N

+UserAgent strings rather than stick with one. Does this approach help,

+hurt, or not matter? Consider: cookies and recognizing Torbutton users

+by their rotating UserAgents; malicious websites who only attack certain

+browsers; and whether the answers to question one impact this answer.

+</li>

 </ol>

 <p>