Speaking as someone who knows their way around cryptography and protocols, and has happily hacked on SMTP/POP3/IMAP clients & servers, what *exactly* is the reason why @Tutanota and @protonmail don't support these protocols and/or external clients?

Because all I can see are downsides of this.

Fuck, we shouldn't have to ask for interoperability in 2022.

@jens Inb4 "We need to be a silo and control all aspects. For your own good you understand."

@espen That is what it smells like. FWIW, mailfence and countermail provide access. It's clearly not impossible.

@espen Because, let's be clear here... both Proton and Tutanota have my signing keys.

I understand the principle by which they operate well enough, I think, but it leaves plenty of opportunity for them to know these keys.

It really seems like a "trust us we don't, and in the meantime we hold your data hostage" kind of deal.

I'm liking it less and less.

@jens @espen don't forget tutanota have lied about what they open source. Protonmail are bad but at least they're mostly consistent.

@jens RIP your mentions!

Conjecture follows.

I think that it falls out logically from their commitment to “end-to-end encryption”. SMTP, at best, is encrypted from MTA to MTA, which means a message is at rest on a server somewhere until it is fetched over IMAP or POP for the last mile. Even if the message body is encrypted using PGP, there’s still metadata in the headers and envelope, and I feel that those services consider that an unacceptable attack surface.

@futzle I'm not saying your interpretation is wrong. You're very probably right.

But they neither explain that, nor do they balance this against the lack of interoperability. Which very definitely creates silos they control, and that very definitely is an attack surface - clearly not one they consider unacceptable, but for me, that increasingly is the case.

@jens Oh, the cynical side of me definitely thinks that there's an element of vendor lock-in happening here, that it's a convenient side-effect of SMTP not offering end-to-end encryption, and that they are absolutely playing on the paranoia of the people who think they need E2EE.

@futzle @jens I'm fine with the silo for Proton, having been a user for some time now. Lack of smtp isn't bothering me. My mail resting on Google's servers bothers me.

@WanderingBeekeeper Well absolutely, if those were the only two alternatives then I would also have an account with ProtonMail. @jens

@futzle @WanderingBeekeeper I have an account with ProtonMail, and for a single user, it's just fine.

Extending this to a company wide email solution is much, much harder, because the lack of SMTP means it's not really possible to integrate it with any notification-by-email sending things. Just to name one example.

We have hand wringing discussions on on how ActivityPub is or is not standardized enough to cross software packages, but somehow it's OK for Email providers not do offer it?

@futzle @WanderingBeekeeper In *no* way do I want to tell people not to use these solutions.

But I absolutely want to call the companies out for the disservice they do the open internet.


About that, #ProtonMail does two very bad things :
1 - its support is using an american software and/or company, Zendesk.

2 - they show every message with a locked lock, as they are "saved encrypted to disk". Only the color of the lock changes to show that it is (or not) end-to-end encrypted.
Which means that it's very easy to mistake an unsecure communication for being secure while it is not.

@futzle @WanderingBeekeeper

@jens for authentication they send you your symmetrically encrypted private key with which you then have to sign a challenge,,, and i think this scheme is not implemented in any other mail clients than theirs?

academically, it's pretty cool, in my opinion, and guess they have just committed to that idea ¯\_(ツ)_/¯

@malte That's a neat little thing, but an entirely unnecessary part, except for webmail. If you'd use SMTP, it's pointless busywork.

If they really wanted to use that scheme for SMTP AUTH, I'm sure the IETF would welcome a draft.

@jens @malte If the world would go down that path it makes more sense to stop bolting on things to pretty outdated protocols and work on something like JMAP instead.

@jens probably because they’d have to expose their cryptography algo? I haven’t used tutanota, and only used proton for a few days (for testing) so i have no real idea, so take this with a grain of salt, obvs.

@gergely in order to send email outside, they have to use understandable aka standards based algorithms.

@jens When I switched away from Protonmail, I used their bridge application on a laptop to provide SMTP access:

Provides an SMTP service on localhost, which you can authorise to access PM accounts.

My reason for moving away was 'Can't use my choice of mobile app'.

In the end I settled for a paid but not E2EE mail service with standards support.

@torclodd It's not really feasible to run such a bridge just to connect to a remote service.

@torclodd Also, and not to put too fine a point on it, Proton and Tutanota are not more E2EE than any standards based system, unless you send from one address to an address with the same provider.

For talking to outside addresses, you have to use standard, and then the bulk of data is E2EE, with some metadata being visible.

One could easily fudge the address such that not much of that leaks, too. At which point there isn't much envelope information left that is open (TL;DR).


Sadly, no matter what brilliant tech you can set up on your own mailserver, sooner or later, you have to email someone with a 10-year-old external host running an ancient SMTP service. So you can either send it unencrypted (over TLS) or force them to deal with manually decrypting it.

Both Proton and Tutanota offer a solution for mailing externally; Tutanota sends links to read the encrypted message on a web interface (you have to share a password out of band 🙁), Proton supports external PGP (you have to get your recipient to use PGP 🙁).

@jens Why should they? Those are email protocols and clients. Walled gardens don't talk open standards.

@jens @Tutanota @protonmail @emacsen are there any e2e at rest services that aren’t walled gardens?

@jens Feels like Autocrypt and Mailvelope are good interoperable approaches. Also @delta’s approach is very interesting.

But email, man… why can’t it just die already? (*sigh* I know, I know…) :)

@Tutanota @protonmail

@aral @delta @Tutanota @protonmail I like the interaction format. I'm also pretty much convinced a standards cleanup would be good.

@aral I'm glad it is still alive. Beside all of its deficits it allows powerful message management: thread-view, filtering, SIEVE sorting, messages come to me (as opposed to web based forums), several identities (as ippossed to WhatsApp, Signal, ertc.)

I've not seen any alternative for this yet.

@jens @delta @Tutanota @protonmail

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