Testnet KeyPackage Registry

[jazzz]

Problem

MLS KeyPackages contain the required material to add a new member to a GroupChat. Passing KeyPackages out of band is not viable given the size of ML-KEM keys.

There currently does not exist a way for a Group Participant to add another by account address.

In the future this will be perform by a robust service likely using λLEZ. However there is more careful thought required to execute on that.

Whats needed

There is a current need for a Service which provides these KeyBundles. The service will be eventually replaced in V0.3, so it only needs to provide the bare minimum in functionality.

• LocalIdentities can submit KeyPackages to the service
• Clients can fetch a KeyPackage for a given LocalIdentity.
• LocalIdentities can submit new Bundles.
• Service stores the latest N KeyPackages for a given LocalIdentity
• Service only accepts KeyBundles from the the correct LocalIdentity.
• Service retains KeyBundles for N days.

Suggestions

• Implement KeyPackage submission via LogosDelivery. Clients publish to a fixed topic, All Service instances listen.
• Implement Fetch however is easiest.