Yes, by default Delta Chat generates an edd25519 key (it uses GitHub - rpgp/rpgp: OpenPGP implemented in pure Rust, permissively licensed btw). As to generating additional keys, we need to be careful to not cause more confusion for those people who try to manually manage keys. We are also slowly starting to consider how to move to OpenPGP V6 keys (see rpgp/docs/FAQ.md at master · rpgp/rpgp · GitHub for what rpgp devs are up, who are also involved with DC core development partially) and that would probably be a good time to consider such “second keys” and then see if they can be used in QR-codes/invite links. This will all take a while – and crypto-things should not be rushed anyway, as we prefer reliability and stability and avoidance of what is known in the matrix world as “UTDs” – “unable to decrypt” issues which Delta Chat users only rarely encounter these days and we’d like to keep it at that 