> Deltachat also embodies some of the best parts of email encryption
It also embodies all of the metadata associated with it, which is still not encrypted.
> Open federation based on the popular and well known SMTP standard
and inefficient for messaging protocols, attachments are literally base64 encoded, every message includes a heap of metadata.
For transient communication you're better off installing a purpose built client with a purpose built protocol rather than trying to butcher email to do it.
This replaces the subject with "...", however if I send that email to someone who doesn't support that every email I send is going to have the same subject, making it difficult for them to easily find the "correct" email from a group. Protonmail for example doesn't support encrypted subjects.
With Matrix for example the only real metadata is room id, and flow of events (what Matrix ID is in what room). You can have rooms which are centralized to a specific server and then that's not an issue.
It will be interesting to see where P2P functionality leads in the future. https://matrix.org/blog/2021/05/06/introducing-the-pinecone-... I think with any long-term identity, it's going to be trackable to some extent, so that is up to specific threat model, whether you get worried about that.
With Signal and Sealed Sender https://signal.org/blog/sealed-sender/ even less metadata is available, although this centralized model is not without downsides such as being operated by a single entity.
> Yeah, the world definitely needs more "purpose built" protocols...
With protocols like olm, you also have concept of different devices, device keys, which can be revoked, and shifted without having to ditch all your keys at once. Cross signing means new devices can be "trusted".
It also embodies all of the metadata associated with it, which is still not encrypted.
> Open federation based on the popular and well known SMTP standard
and inefficient for messaging protocols, attachments are literally base64 encoded, every message includes a heap of metadata.
For transient communication you're better off installing a purpose built client with a purpose built protocol rather than trying to butcher email to do it.