[verandaguy]

I used to be skeptical about this... but if the Signal protocol sees more widespread adoption outside of the Signal app and Whatsapp, it could be a good fit.

I'm very open to hearing about reasons why this wouldn't be the case, though.

[lmm]

There are times when you want non-repudiable signatures, times when you want to be able to keep an archive, times when you want your messages to behave more like letters than like spoken conversations. PGP is still the best fit for email-like use cases and long-lived identities; Signal et al don't even try to address that use case.

[CaptSpify]

AFAIU, the Signal protocol doesn't work with email, only with sms. Am I mistaken in this?

[mstef]

the protocol is very generic and does not require anything related to phones. it is actually 3 parts, a key exchange, a signature mode and a ratchet. how you combine these is up to you. the app is one way to combine them with phones. there's other ways to use the protocol, that could also be applied to emails

[wtbob]

There's no reason why the Signal app couldn't allow you to register mailto:[e-mail] as well as tel:[phone]; it just, currently, doesn't.

And of course the protocol in general is much higher-level than that.