On 9 January 2013 10:05, Alexandre Guillioud <guillioud.alexan...@gmail.com> wrote: > Hi all, > > I'm reading your conversation, and i'm not understanding very well what you > mean by high/low latency network. Isn't it just a ping duration delta ? > You speak about low and high latency like it's a feature. > > Is tor mixing only low latency with low latency in its circuits ? Opening > for a dispatching of services (ie. mail on high latency, web on low ) ? > > What's the point ?
Someone can probably explain it better by putting more time into it, but the gist of it is how long a mix node will 'hold onto' a message, before sending it on. (Effectively 'mixing' it.) >From the blog articles: > A 'Low Latency' mix network means as soon as a node receives a packet, it > sends it out. A 'High Latency' mix network means a node will hold onto a > message for some amount of time before sending it out. > > Traffic Analysis is a huge part of mix network design. If an attacker is > watching the network (and we generally assume they are) - how much > information do they gain by watching packet paths, sizes, and times, and how > easy is it? If you see a network flow from Alice to Bob, and Bob to Charlie - > those flows will probably be matchable. With regard to defending against > Traffic Analysis, High Latency is preferable - being able to hold onto a > packet for any length of time before sending it on gives you lot more options. > > Tor is a 'Low Latency' mix network - it has no choice because it's infeasible > to browse the Internet with minute-long (or longer) delays during page loads. > However, email can have delays - if an email doesn't arrive for 30 minutes or > an hour, it's generally not a problem. So Remailers can afford to be a High > Latency mix network. They will accumulate a number of messages in a pool, and > then when the pool is a certain size, will send the messages out. There are > multiple algorithms for pooling, and we'll go into more detail about them and > pool attacks later. As a mix node, if I accumulate 8 same-size messages, and then send them all out at once to 8 recipients, you can't use traffic analysis to see who I sent which message out to - because they're indistinguishable. That's high latency. But if I had sent out each message as soon as I got it, you could see which message went to each recipient - that's low latency. -tom _______________________________________________ tor-talk mailing list tor-talk@lists.torproject.org https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-talk
