The fastest and easiest way to send end-to-end encrypted email in Proton Mail is to have both ends of the conversation use Proton Mail. In emails between Proton Mail accounts, the PGP encryption takes place automatically behind the scenes, with no technical expertise required.
However, if using Proton Mail is not an option for your contacts, there are two other methods to send end-to-end encrypted email in Proton Mail: Password-protected Emails(new window) or external PGP encryption.
External PGP encryption is an advanced Proton Mail feature that allows you to send encrypted emails to non-Proton Mail email addresses using the recipient’s public key. This feature is also supported in Proton Mail Bridge, but it requires some additional configuration in the web app.
Adding your recipient’s public key
Setting up encryption so that Proton Mail automatically encrypts messages sent to a specific non-Proton Mail recipient can either be done by manually uploading the public key of the recipient into Proton Contacts or by asking the contact to send you an email with their public key attached.
You can learn how to add your contact’s public key in our guide How to use PGP(new window) (see Sending PGP emails section). We recommend reading the entire article before using PGP in Proton Mail.
It is not possible to do this within your mail client or in Proton Mail Bridge. To add a recipient’s public key to their contact, you must log into your Proton Mail account at mail.proton.me.
Once you have added the recipient’s public key, you can send them emails normally, and they will be encrypted automatically.