sudneo

Sure! FYI, simplelogin can create aliases with prefix! I usually get service-{random 5 chars}@simplelogin.com, so you can still sort by folder using prefixes.

You should definitely be! I take backups every 6h for my self hosted vaultwarden (easier to manage and to backup, but not official, YMMV). You can also restore each backup automatically and have a "second service" you can run elsewhere (a standby basically), which will also ensure the backup works fine.

I have been running bit/vaultwarden now for I think 6 years, for my whole family and I have never needed to do anything, despite having had a few hiccups with the server.

Don't take my word for it, but the clients (browser plugin, desktop app, mobile app) are designed to keep data locally I think. So the term cache might be misleading here because it suggests some temporary storage used just to save web requests, with a relatively quick expiration. In this case I think the plugin etc. can work potentially indefinitely without server - something to double-check, but I believe it's the design.

Interesting! That's very close to this blog post I read long time ago (unfortunately medium.com link)! Are you actually sending emails from those addresses? Like if you need to drop an email to your bank, do you use the banking one or your personal (or something else)?

Fwiw, I do something similar. I use a mix of domain aliases without address (e.g. made-up-on-the-fly@domain.com) and actual aliases. Since I have proton family (and the same when I used ultimate) I have unlimited hide-my-email aliases, so I have it integrated with my password manager, and I generate a random password and email for everything I sign up now. These though are receive-only addresses. In fact, with this technique I probably use 3-4 addresses in total, but I have probably 30 domain addresses that go to the catch-all one.

Spam on these addresses are basically non-existing and you can still create folders based on recipient without having a full address (e.g. bank1@domain.com, bank2@domain.com). You can make folder categorization based on recipient regex and this way you also have the "stop bothering me" option: if some email gets into the wrong hands, you can create a spam rule for that dedicated address. However, my approach is that all of these are used just to receive emails, to send I have just a handful of actual addresses or -if really needed- I can create on-the-fly an address from a catch-all one, send the email and then disable it again (so it doesn't count towards the limit, but I still get inbound email to the catch-all).

Nice setup anyway!

Your requirements are totally fair tbh.

That said, I think you can use aliases for the use-case you have, you don't need full addresses. Proton supports "+ aliases" as well, so name+service@domain works, and most importantly they support catch-all addresses if you have your own domain. I now use actual aliases (the ones from simplelogin), which I generate on the fly, but if you can use whatever@domain and it will be redirected to your configured address. You don't even need to create this beforehand, so many times I was around and had to give an email address for some reason and I just made up an address on the fly. As long as you use your domain, the catch-all will get the email.

So the 10 addresses only include actual addresses, the ones you can write from. You can have as many as you want to receive emails (which is generally the use case for signing up to services, right?). Just a FYI in case tuta supports the same and you are making more effort than needed!

If XMPP were to replace emails, that would’ve been great

Who knows :) But XMPP also needed all kind of extensions to support even relatively old security measures.

Anyway, I still don’t trust Proton. Have a great day.

That's fine, you can trust who you want, of course. The important thing is to have clear the risk model.

Encrypted or not, the fact that someone else has it stored somewhere in their computers is dangerous.

Of course. You are simply over-representing this risk, though. Besides, regular people realistically don't need to worry about Proton being backdoored, because their device is 10-100x more likely to be breached instead. Security is not a binary, it's a shade. Performing a software update is also "dangerous". Do you check every time you update the software its code, to verify no malicious backdoor is there? No, exactly, you trust the maintainers and the package infrastructure.

The only recommended way to store private keys are offline and encrypted.

So you don't store them on your device(s) (encrypted)? I store my GPG keys that I use to sign software on my yubikeys. That said, email is something I check from my phone and multiple computers (as most people). Do you really use a hardware key to do on-the-fly decryption, every time someone sends you a message, from each device?

As a security engineer, I also generally discourage such absolute "recommendations". My threat model is different from a regular Joe threat model, and both are different from Snowden's. There is no such thing as "only recommended way", because this is not a religion, it's a risk decision. Most people use Gmail, where the content of their email is literally available server side. Those same people can gain privacy and security using GPG via Proton, and in their threat model "provider gets compromised and software backdoored" is completely irrelevant. Is it relevant in your threat model? Good, then yes, you should only store keys offline and encrypted. Actually, you shouldn't use email at all, and you should use dedicated tools and protocols that are meant for security, where metadata is not transmitted in clear text, for example. You should also have virtually no session duration and perform a full login with 2FA every time, you should probably access the software that you use to communicate only from a secure machine dedicated for the purpose etc..

I think you trust Proton a bit too much.

I simply have clear in my mind what my threat model is and what risks are acceptable. I perfectly fit in the "Anyone with privacy concerns" category in the threat model they built. What about you?

Oh that makes sense. Yeah, definitely simple encryption and exported (unencrypted) emails are not going to work together.

I am all in support for European tech companies, so I think that mailbox.org, tuta, proton etc. Are all good options.

From what I read though, the GPG security model for mailbox.org is the same as it is for Proton webmail (except for the browser plugin, where the difference is not really there). I like mailbox.org, to be clear, but I don't get how it is an alternative to the bridge.

I can't comment on this, since I don't use the bridge for a while. But it's just an IMAP/SMTP server, so not sure why certain features wouldn't work. What service did you end up using which has gpg integration?

One of the biggest risks is when someone knows your password.

Just a curiosity. How do you think every password for every online service works? The service "has" your password. It is hashed, but if this doesn't matter (similarly for encryption) to you, then you should be panicking about basically everything.

In the case of Proton an attacker has basically these options:

• Option 1: Attack you, try to compromise your device. If this is the case, your local keys are going to be taken, one way or another, even if you have them locally and encrypted. The only way you might save yourself in this scenario is if you store them on an hardware device (like a yubikey).
• Option 2: Attack proton. Once the infrastructure is compromised, the JS code that does the crypto operation needs to be backdoored, you need to use the service while the JS is compromised, and the attacker will obtain the keys and the messages.
• Option 3: Compromise the sender/recipient for the emails (this is in cleartext in any case).

In the case of a manual solution:

• Option 1 is identical.
• Option 2: Attack the software you use (let's say, mutt). Once you gain access to the repository, push a backdoored update and wait for you to install the new version. Incidentally, compromising this tool also allows the attacker to compromise your whole machine (unlike what happens with JS code, which runs at least in the browser sandbox).
• Option 3 is identical.

So the tradeoff is really that:

• With Proton an update is going to be pushed quicker and without your explicit interaction, but
• compromising Proton is going to be much, much harder than compromising the laptop/repository for the handful of maintainers that generally have the keys to push updates for the software you are most likely going to use. We are talking company with security department + SOC vs maintainers with whatever security practice and no funding.

It’s not even hard to manually encrypt emails.

Yeah, and this is why 99.9% of the people have never and will never touch GPG with a 10-foot pole. The tradeoff is a complete no-brainer for the vast majority of people, because the reality is that for most, either someone else does the key discovery, management, signing, encryption, decryption, or nobody does. We can sit here and pretend that it's easy, but it's not. Managing keys is hard, it is painful, especially on multiple devices, etc..

EDIT:

The entire threat model for proton is also documented BTW: https://proton.me/blog/protonmail-threat-model

Introduces some risks in terms of security. Privacy concerns are extremely minimal, because in any case you don't control the setup of your other interlocutor(s).

Considering that the realistic alternative is not using anything at all and the fact that you have both options with Proton, it's a win-win scenario.

There is a reason: simplicity. Either you do all the key management yourself, which in practice means 98% of the people won't do it at all, or you implement a solution like they did and increase the risk of a small % (see my other comment) but you cover every customer.