Provide a cryptographic implementation for Qaul.net

Hey there,

my name is Katharina (aka spacekookie) and I am one of the Google Summer of Code participants for Freifunk projects; qaul.net in particular.

I wanted to write up a short article on what it is I will be doing this summer, how I will do it and what I hope to achieve. This will be one of three articles published on this blog.

Qaul.net provides a mesh-wifi network for people to connect and share information to other people on the network. Like freifunk it uses the OLSR mesh routing library. But unlike freifunk it’s main goal isn’t to connect to the www-internet but rather create a network of it’s own on which people can communicate, share data and come together. No centralised infrastructure required.

Currently all traffic on qaul.net is sent in the clear which is…suboptimal. For one nothing said on the network is in any sense of the word “private”. On the other there is no way to verify identities. And that’s what my Summer of Code project is about.

The changes to the qaul.net code base required are quite extensive but with a bit of clever planning shouldn’t break too many things. The core thing required is an abstraction layer between user and network.

Currently a user gives their node a nickname and that’s then them. “Identify verification” (if you want to call it that Tongue Out) is done by checking IP addresses against nick-names. Man in the middle attacks are very easy in such a network and the only defense is the benevolence of its users.

What I thus plan to do is introduce an abstraction layer between a node, routing and what a user sees. A “user identity” which can be shared between different nodes (but doesn’t have to be), something that can be written to an addressbook and is later on verifiably the same and will make users aware if their are being man-in-the-middled, which is now much easier to verify.

In addition to that I plan to introduce asymmetric encryted messages, completely transparent to the user. While qaul.net can flood a message acress the network that should be seen by as many people as possible, there should be the ability for two people on the network to talk to each other without anybody else knowing what they’re talking about.

What’s planned is something that resembles PGP. A users identify will be their master-private key fingerprint. From that each node gets a subkey-pair (public and private). The public key will be flooded into the network for people to use to write messages to that node. The private will be unique to the node. And when sending messages to another person people can either choose “all” which means that the messages is encrypted against all (non-revoked) public keys of the target identity or choose a specific node to talk to. This implementation also allows for mailing list style group discussions.

 

Through Google Summer of Code I hope to become a regular contributer to qaul.net as I am a big fan of the project ideas. I also hope that my contributions will make it a much safer place to communicate and share information on.

As already mentioned I will be updating this blog two more times: one around the half-way point of the project and one as a wrap-up of how it all went.

If you’re interested in reading more of my insane ramblings about the project, maybe micro updates and what not, check out my personal blog https://spacekookie.de or go directly to the GSOC category.

 

Until another day,

Katharina/ spacekookie

 

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