How to check a TLS/SSL certificate

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 is always encrypted and protected by HTTPS(nueva ventana).

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 a TLS certificate that is verified by a trusted certificate authority. The certificate authority that vouches for proton.me is Let’s Encrypt(nueva ventana). A modern browser should automatically check the validity of the certificate of an HTTPS-protected website and alert you if it detects something untrustworthy.

How to check your certificate issuer

Chrome

1. Click the controls icon (view site information) in front of the URL. Then click Connection is secure.

2. Click Certificate is valid.

The TLS certificate will appear in a pop-up.

Firefox

1. Hover over the Shield icon in front of the URL. A tooltip will appear, showing the certificate issuer.

2. To open the full certificate, click the shield then select Connection secure.

3. Click More site information > View certificate.

Safari

1. In the navigation bar, click Safari then select Connection Security Details… from the menu.

2. Click Show Certificate.

3. Click Details to show the issuer’s name.