Modern Mix Network Design

(David Stainton) #1

Hi! I’d like to give a talk about mixnets. I am currently working on the Katzenpost project ( ). Below is the talk description:

I shall explain the renewed interest in mix networks. Like Tor, mix networks protect metadata by using layered encryption and routing packets between a series of independent nodes. Mix networks resist vastly more powerful adversary models than Tor though, including partial defense against global passive adversaries. In so doing, mix networks add both latency and cover traffic. I shall outline the basic components of a mix network, touch on their roles in resisting active and passive attacks, and discuss how the latency impacts reliability, application design, and user experience. In particular I’ll mention how mix networks can be used with messaging applications and crypto currency to resist network surveillance and traffic analysis.

Academics have proposed various anonymity technologies with far stronger threat models than Tor, but by far the most practical and efficient option remains mix networks, which date to the founding of anonymity research by David Chaum in 1981. Tor was inspired by mix networks and shares some superficial similarities, but mix networks’ are vastly stronger if they judiciously add latency and cover traffic.

There are several historical reasons why mixnets lost popularity and why Tor’s onion routing won. Namely, Tor is low latency and really good at being usable. This is in contrast to mix networks which are essentially an unreliable packet switching network. Historically mix networks achieved enough mix entropy by using long delays whereas it is becoming more widely understood that there exists a trade off between legit traffic, decoy traffic and latency. After this introduction to mix networks I’ll talk a bit about the Katzenpost mix network software project which is based off of the recently published academic paper “The Loopix Anonymity System”. These new insights into mix network designs allow modern mix networks to make the correct design trade offs so that we can keep the latency relatively low. Historically high latency and unreliability has been a major obstacle to mass adoption. I shall explain how Katzenpost solves both of these problems and allows developers to easily add network services to the mix network to support a wide variety of client applications including but not limited to: messaging/chat, crypto currency transaction transport, offline browsing, file sharing, bulletine board systems et cetera.

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(Redon Skikuli) #2

This seems quite interesting David. Can you please propose a date and time? Please keep in mind the events that are already planned: Please avoid Saturday 14.07.2018 because it seems quite full with a members meeting (members only) and a workshop. Looking forward :slight_smile:


(David Stainton) #3

How about I give this mixnet talk on Friday July 6th?

I’d like it to be interactive so that people can feel free to interrupt me and ask questions. I have some slides prepared but I can also just draw diagrams on a whiteboard.

(Elio Qoshi) #4

That looks good to me! As I said via email as well, Simone is in town so maybe we could have a joint talk to discuss about Mixnets, Tor and OONI if you are open to that. What do you think?

(David Stainton) #5

I don’t want to do a joint talk as Tor and OONI are not related to my work on mixnets.

My talk will only talk about Tor so that I can mention how it’s threat model compares to mixnets.

(Elio Qoshi) #6

I more meant to have those sessions at the same day adjacently under an event umbrella. We can do something solely mixnets focused only as well though.

(David Stainton) #7

Yes having various talks on the same day sounds good to me!

(Elio Qoshi) #8

Sounds good. Should we go ahead with some time afternoon Friday?

(David Stainton) #9

Yes. Sometime. I don’t have any preference except not too early in the morning.

(David Stainton) #10

How about having my talk at 6pm and then some other talks afterwards?

(Elio Qoshi) #11

Sounds good to me! Let’s do it

(Redon Skikuli) #12

Thank for organizing this guys. @elioqoshi can you please add the info on our wiki? This will help people have more info about the date, time and other details of the event.


(Elio Qoshi) #13

Just woke up and this is the first thing I will be doing today :slight_smile:

(Elio Qoshi) #14

I will add the OONI Probe Workshop right after it around 7:30PM I’d suggest.

(Elio Qoshi) #15

Event on the Wiki live:

(Elio Qoshi) #16

Also the OONI Workshop: