otrv4 / otrng-prekey-server

Prekey server functionality for OTRv4. This is a mirror of https://bugs.otr.im/otrv4/otrng-prekey-server

OTR Next Generation Prekey Server in Golang

This project aims to provide Prekey Server functionality for the OTRv4 specification. It is an implementation of the OTRv4 Prekey Server specification, that can be found here: https://github.com/otrv4/otrv4-prekey-server

The repository aims to provide generic prekey server functionality, and XMPP specific tools in a separate package.

otrng-prekey-server's Issues

Implement zero-knowledge proofs for public values

The OTRv4 Prekey Server specification has been updated with support for verifying public values. We should implement this.

• implement proofs
• add serialization of proofs
• add proofs to publication message ser and deser
• add proofs to MAC
• add verification of proofs to validation of publication message

Support forging keys in Client Profiles

After updates to OTRv4 to add forging keys (otrv4/otrv4#177) we need to implement support for the new client profile format in the prekey server, and make sure we validate the public forging key values as well.

Add a ZKPK of the private keys associated with some public values

Specifically, we would need proofs for:

• ClientProfile public key
• ClientProfile DSA key
• PrekeyProfile shared prekey
• PrekeyMessage y
• PrekeyMessage b

The only flow that needs to be changed is the publication message:

Once the server gets a publication message, it sends back challenge values for each one of the values we need. The client generates the challenges, sends them back, and the server returns success or failure.

We also need to remember that we need to tie the shared secret from the DAKE into the proofs.

We should ratchet the following MACs for these values.