I have this proposal for ActivityPub

NOTE: This proposal is based on https://www.w3.org/TR/activitypub/#authorization and https://www.w3.org/wiki/SocialCG/ActivityPub/Authentication_Authorization consulted on 06 January 2024.

• Considering that the entire section on safety considerations is presented as non-normative
• Given that "at the time of standardisation there are no strongly agreed mechanisms for authentication. " as per the above reference
• Assuming that the ultimate goal is to have a decentralised, persistent and verifiable identity.

Premise: The following proposal represents a radical and potentially disruptive change to the current ActivityPub specifications. In particular the following parts:

• ActivityPub clients authenticate to a server using OAuth 2.0 bearer tokens.
• Related OAuth considerations

It is also important to note that the following proposal can coexist with current OAuth authentication.

The proposed encryption algorithm (ED25519) can and should be updated in the event of a vulnerability or major upgrade.

Suggestion

I have no idea how to write a document like this correctly, and I am probably doing it wrong, but my only goal is to stimulate discussion.

The proposal is as follows.

ActivityPub clients authenticate against a server using ED25519 signatures In general, bearer tokens can be easily replaced by signatures in almost every aspect. Advantages:

• Servers don’t need to store anything other than a session token.
• Authentication is decentralised and context independent
• Your key is your identity: no server breach can expose your data
• There are mature libraries like node-forge (for nodeJS and TS) and many others that allow easy implementation of authentication.

I have tried to think about possible downsides, but the goal of this post is to stimulate discussion, please keep it respectful, but of course criticism and additions are welcome!