Proton Mail’s TLS/SSL Certificate

NOTE: Proton Mail(new window) may use different TLS certificates for our subdomains. The information below pertains only to our main site proton.me(new window).

Proton Mail is all about privacy, and we want to do our best to protect everyone’s data and communication. When accessing proton.me, the transmission of information between your browser and our servers in Switzerland is always encrypted and protected by HTTPS(new window). While this is not the same as the end-to-end encryption concept of PGP, it is nevertheless important for protecting you from man-in-the-middle attacks and other forms of communication eavesdropping.

For HTTPS to work, each website must have an TLS certificate that is verified by a trusted certificate authority. The certificate authority that vouches for Proton Mail is Let’s Encrypt.(new window) A modern browser should automatically check the validity of the certificate of an HTTPS-protected website and alert you if it detects something untrustworthy.

To check the certificate issuer in Chrome:

1. Click on the lock button in front of the URL
2. Click on Certificate
3. Go to the Details tab

To check the certificate issuer in Firefox:

1. Click on the lock button in front of the URL
2. Click the arrow next to Connection secure
3. Click More Information
4. Go to the Security tab

To check the certificate issuer in Safari:

1. Click on the lock in the address bar.
2. Select Show Certificate.
3. Select Proton Mail and then Details

We will continue to improve our security protocols and roll out more security features as we scale up. Thanks for all the interest and help from the community!