Re: [Help-gnunet] Building a new censorship circumvention tool: what do we need to know?

[Jeff Burdges]

On Mon, 2017-02-20 at 11:02 +0100, Ivan Vilata-i-Balaguer wrote:
> At eQualit.ie we're beginning a project to develop a new Free/Open
> Source censorship circumvention system based around the idea of our
> original [CeNo project](https://github.com/equalitie/ceno), a system
> which uses the Freenet P2P platform to retrieve web content and make it
> safely available under censorship conditions.  We're keen to evaluate
> existing options, projects, technologies and approaches so we're
> conducting something of a literature review.

Howdy,

I'm our resident mix network guy so I'll rely.  Right now, I'm writing a
mix networking library in Rust to provide a Sphinx-like packet format
with single-use reply blocks (SURBs) and a ratchet scheme to enhance
several cryptographic properties. 

I have discussed Ceno with Richard King several times.  And I suggested
the Tor project look into Cero for solving their ClouFlare CAPTCHA
problem a few times too.  At present, there is a browser plugin by
Yawning that forwards CloudFalre CAPTCHAs to archive.is.  

There are various people involved in early stage projects to build mix
networking software, including the Panoramix project.  We're holding a
meeting on mix networks after the Tor dev meeting in Amsterdam in late
March.  I'll send you a separate invite to some conversations around
that.  


> With this purpose, we're reaching out to people involved in similar or
> related projects.  We'd love to hear what you think is the current state
> of the art in this area, and particularly about technologies you'd
> describe as trustworthy, reliable and established.  In particular, we're
> looking for tools that have one or more of the following properties:
> 
>   1. Content is available under censorship conditions, ideally even
>      after connection to the Internet has been completely cut for a
>      whole region.

I'm not familiar with the mesh networking stuff in gnunet's transport
layer, nor even the current level of activity there, but something
exists.

>   2. Censored content is made available within a reasonable time.
>   3. Access to censored dynamic content (i.e. web apps) is possible.

We have folks working on "social" protocols, but the threat model gets
very tricky here.  Also GNS sounds relevant

>   4. The system benefits from the user's participation, and is resistant
>      to participants dropping off and to rogue nodes in the hands of the
>      censor.
>   5. Users of the system are anonymous to someone observing their
>      traffic, even if that someone is a participant in the system.

These two part I know about.  :)

>   6. Users' devices don't reveal the content that they or other users
>      have accessed.
>   7. The system is amenable to privacy-preserving analytics to check its
>      impact.

I'm not sure what you mean exactly, but these two sound fraught with
distractions.  Tor has many people who worked on 7.  We do have ideas
around network size estimation that might be relevant depending upon the
scale and network properties.

Also, we have an anonymous web-based payment system called Taler that
should eventually fit into all this :  https://taler.net/en/
It's currently focused more on the low latency use case, ala Tor, but
higher latency variants make sense.

> By the way, part of the team will be at the upcoming
> [Internet Freedom Festival](https://internetfreedomfestival.org/) in
> Valencia (6-10 March).  If you plan to be there we'd love to chat with
> you face to face.`:)`

I am coming to IFF and several other meetings in March, so I'm happy to
chat.  :)

Jeff

p.s.  There is definitely an interest in a high latency browser built
from Ceno plus a mix network because folks are increasingly recognizing
the limits of Tor.  At present, I believe most folks independently
interested in mix nets want to focus on "new applications" designed to
be tolerant to latency, primarily simple messaging applications to
replace email, but I think the Panoramix exists primarily for voting,
not sure how much they cover messaging.  There is however an issue that
messaging does not generate much traffic, which makes hiding harder.  I
think high latency web browsing makes a good way to fix this.

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