As a first step towards adding Object Integrity Proofs (FEP-8b32) to #Fedify, I've made it support #Ed25519 keys. I've also enabled multiple keys to be associated with an actor. For example, if you look at the actor from the Fedify Example Blog (https://fedify-blog.deno.dev/users/fedify-example), you'll see that it has two public keys, one for RSA and one for Ed25519.
You can try it out in version 0.10.0-dev.190+4dffb89a.