With this update, you are now able to share your calendar end-to-end encrypted. As only Premium users can add additional calendars, people you share your calendar with need to use Tutanota Premium.
In this video you can learn how to share your Tutanota calendar.
The sharing feature is a very advanced, technically complicated feature. It is designed as an add-on feature that is not included in the email packages Free, Premium or Pro. Please check the pricing calculator at the end of our pricing page for details. The sharing feature will evolve into a collaboration feature (sharing drive data, etc.) without raising the price then.
By booking the sharing feature, you can share multiple calendars with an unlimited number of Tutanota users. Any changes made to the shared calendar are instantly synchronized to everybody you shared the calendar with. Upon sharing, you can choose between several permissions for the recipient:
Even when sharing your encrypted calendar, all data contained remains securely encrypted, and only the people you shared the calendar with will be able to decrypt the data locally on their devices.
For sharing the encrypted calendar, we use asymmetric encryption. The data is encrypted with a symmetric group key that is encrypted with the public key of each user that the encrypted calendar has been shared with.
This way each user that the calendar has been shared with can decrypt the encrypted calendar while we as the provider as well as any other third party remain blind to your zero-knowledge calendar.
Due to the end-to-end encryption, you can not share your Tutanota Calendar with outside users. If you want to share your calendar with someone who is not yet using Tutanota, please invite them to our secure email service.
Along with this update, we are also changing the payment process to a credit balance system. This is a requirement for being able to process Bitcoin payments, which we want to enable in the coming months. Please check our roadmap to see the status on lots of upcoming features.
See the full release notes here.