Proposal 1.1 (P11)

aka pEp onion routing/remailer?

This is an attempt to transcribe V. ideas after juga’s presentation on January 12, 2021 [MixmailerSlides] and some other comments with N. and D. These are not juga’s ideas.

As D. noted, it should probably not be called mixnet.

This proposal very similar to Proposal 1 (P1) design. The main difference seems to be not aiming to implement a mix network but just onion routing, which it is actually simpler.

Any mention to prototype means this: [Mixmailer]


As in Proposal 1 (P1), client decide the route for the message.

The user might also decide.


As in P1. SMTP, no TLS.

Nodes’ keys

Same as in P1. Each node have its own private/public OpenPGP keys.

Keys rotation

Not defined

Key discovery (by clients and nodes)

In P1 it was proposed that nodes/clients exchange messages to discover keys. Then we started to use GNUnet GNS in the prototype. In this proposal we’ll continue with GNS is used to query the list of nodes to the authorities and other nodes’ keys. In the prototype it’s explained in more detail: Mixnet nodes registration in GNS, though the part about layers should be ignored.

Key registration

This is being researched by N.

Types of nodes

All the same. In the prototype juga decided thought it would be better to use stratified topology, but it can be removed.



Packet format

No packets, just messages. Not really MIME Multipart Encrypted (and Signed?). pEp message 2.x? [ref?].

Packet size

Instead of padding in a way that the final messages are all the same few fixed sizes, they’ll be padded randomly. If the final message is too big it’ll be just discarded. This is different to what was tried to implement in the prototype and P1.

Packet mixing & delays

Undecided. If it’s just onion routing, in principle there’s no need for. In the prototype there was just random delays.

Cover traffic


Directory servers/authorities

In P1 it was said that there was no need. Since we started to use GNS, they’re needed. The prototype already assume there’ll be authorities.


It doesn’t exist.

Network diversity

Community will be made.

Nodes and messages diagram

Nodes and messages


Deployment diagram

As the one before, including software components.



Deployment diagram including GNS

As the one before, including GNS.

Deployment with GNS


See Proposals 1, 2 and 1.1 arguments for arguments in pro/con of the several proposals.