Everything you need to keep your schedule private
Protected by the same end-to-end encryption used in Proton Mail, Proton Calendar has all the features you need to manage your events easily.
Need a secure calendar for work? Discover Proton for Business.
Secure by strong encryption
Open source and audited
Private participants
Cryptographic verification
Secured by strong encryption
A calendar is a record of your life and contacts, and it contains some of your most sensitive online data. Proton Calendar helps you keep it safe automatically.
End-to-end encryption
With Proton Calendar, all of an event’s critical information, like the title, description, location, and attendees, are stored securely and privately with end-to-end encryption. Not even Proton can read your event details.
Elliptic curve cryptography
Proton Calendar leverages advanced, high-performance elliptic curve cryptography (ECC Curve25519) to secure your data. This happens automatically in the background without requiring any action from you.
Open source and independently audited
The Proton Calendar web app is fully open source, so the code is available for inspection, and the Android app’s code will be open source soon. Both apps have been independently audited to verify that they actually work as advertised.
Keep participants private
When you invite someone to an event, this information is encrypted so that not even Proton knows their identity. This significantly enhances the anonymity of the participants.
Cryptographic verification
You can invite others to a shared Proton Calendar using a secure protocol that verifies the inviter’s identity. This cryptographic process ensures the invitation is authentic, allowing the invited member to confirm it was truly sent by you.
Cryptographic signatures verify that each data type was created and edited by the designated author, ensuring no one, including Proton, has altered your events or data history.
The cryptographic verification process runs automatically in the background, ensuring security without needing any input or action on your part, seamlessly protecting your data.
Proton Calendar was built by the team behind Proton Mail, the world’s largest encrypted email service
Over 70 million people and some of the world’s largest organizations have signed up with Proton.
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