[ploum]

Proton user here: I’ve an anecdote because it happened this week and support was unable to help me.

I’ve received a PGP encrypted email by a non-proton user. It worked fine. But I was unable to encrypt my reply to him.

Proton support told me that he needs to attach his public key to his message so I can use it.

It seems that the Proton interface doesn’t offer any way to automatically try to find the public key of an user (from which you have an email address and probably a signature).

[twiss]

We do look up keys automatically using WKD. However, if the non-Proton user's provider doesn't support that, they'll indeed have to attach it or you'd have to import it manually.

We have plans to also look up keys on keys.openpgp.org as well, to offer an automatic solution in case the provider doesn't support WKD.

[ploum]

Thanks for the clarification. I now understand better: I was confusing WKD and keys.openpgp.org as same thing.

As I received the email without the key attached and his domain doesn’t support WKD, I was stuck to manually import from keys directory. It makes sense.