SSL Certificate Update

UPDATE 4 Novenmber 2019: We are now using SwissSign AG as the certificate authority to issue our SSL/TLS certificate. Learn more about how to verify’s SSL certificate.

UPDATE 11 October 2021: We are now using Let’s Encrypt as the Certificate Authority that verifies the SSL certificates used to secure the ProtonMail and ProtonVPN web sites. For more information on this, and for instructions on how to check the validity of our certificate, please see ProtonMail’s TLS/SSL Certificate.

On January 20th, 2016, ProtonMail will be updating the SSL certificate for

With this update, we will also be changing our Certificate Authority to QuoVadis Trustlink Schweiz AG. Along with the change in SSL certificate, we will also be moving the ProtonMail secure email service to a dedicated subdomain, We have also released ProtonMail 3.0 into beta. To learn more, please read our announcement post.

These changes will be completely transparent to the user. It will still be possible to log in from our homepage which will stay at The new SSL certificate will be automatically accepted by your browser. ProtonMail 3.0 will also be automatically loaded by your browser on page refresh. If you have bookmarks like, then you may wish to update them to

These changes are part of our continued efforts to improve security sitewide in advance of the major ProtonMail releases that will be coming soon, starting at the end of this month. Moving the webapp to its own subdomain will help to improve security by isolating the webmail from other services and is the first step of our bigger 2016 secure email roadmap.

We are happy to bring on QuoVadis Trustlink Schweiz AG as another partner in helping us provide the world’s most secure email service. After much evaluation, our team determined that QuoVadis is the best Swiss Certificate Authority (CA) for high security applications. Like ProtonMail, QuoVadis Schweiz is a security company, and one of the approved issuers for SuisseID, the Swiss voluntary national e-ID program. They are a government qualified CSP in Switzerland, and an accredited CSP in the Netherlands and Belgium (with EU-wide capabilities). Lastly, they provide the responsive service that is absolutely necessary in the security space where response time is vital.

With QuoVadis, we are able to bring a highly sophisticated SSL certificate to benefit one million ProtonMail users. Advanced features of our new certificate include Extended Validation (EV), 4096-bit RSA, SHA-256 hash, and Certificate Transparency (CT). Together with QuoVadis, we will continue to stay on the cutting edge of SSL certificate technology to ensure the highest level of security for ProtonMail users.

In our discussions with QuoVadis, we discovered that some of them are also ProtonMail users and want to support us in protecting email communications. Given that many ProtonMail users are also businesses with high security needs, we have negotiated a 10% discount for all ProtonMail users who are interested in acquiring certificates from QuoVadis. Simply write to from your ProtonMail account and mention the code *QVProtonPartner* to get the ProtonMail rate.

Best Regards,
The ProtonMail Team

You can find ProtonMail’s new SHA-256 and SHA1 below:

Secure Email ProtonMail's SHA Fingerprints

About the Author

Proton Team

Proton was founded by scientists who met at CERN and had the idea that an internet where privacy is the default is essential to preserving freedom. Our team of developers, engineers, and designers from all over the world is working to provide you with secure ways to be in control of your online data.