A basic privacy and security thing to do would be to not give away any login credential information to anyone...

But of course if everytime we send an email (main address or not) we also send half of our login credential to the recipients, then something have failed in the whole idea to create a private and secure service!

Good point, I am transferring my votes.

kind of duplicate of https://protonmail.uservoice.com/forums/284483-feedback/suggestions/10641012-allow-login-username-to-be-different-from-email-an

I would suggest to people to also vote the one with most votes.

Agree!

All other providers make this distinction by default between main address (= account login) and alias addresses. It is a security feature (more precisely, not making this distinction is a security flaw).

That's a good idea, I asked last year Proton Mail if they have planned to implement this option but so far, no news :/

I'd love to have this. I give out my aliased email to people I know, but I'd like the ability to keep that one from being able to login to the account. That also makes it so if there's a data breach, on say Equifax, where it exposes my email and password, then the hackers can't then try using that on Proton to gain access to my email and some 2FA options.

This is a great idea. A user could use their primary id for logging in ONLY, and use aliases to communicate. This prevents the login id from being exposed.

This is feature currently offered by Microsoft and I would love to have in ProtonMail. the idea is to be able to choose which aliases are allowed to sign-in to your account. This way, if one of your aliases is compromised in a data breach, it cannot be used to attempt to hack your email box.

It would be good for ProtonMail too since it will not have to face multiple attempts to carck to its customers' passwords. The very first attempt would be denied.