397 votesAnonymous commented
I would be satisfied if you could provide an export and download the data encrypted.
According to that: https://tutanota.uservoice.com/knowledgebase/articles/470732-what-encryption-algorithms-does-tutanota-use
you use a hybrid method of encryption.
If you could provide some details about the way we should decrypt maybe the users will create the
code needed and we can decrypt in our computer.
I think the above is not very difficult and it's the fastest solution for you to provide the users a way to access their emails while your service is offline or for backup reasons.
Also I do no not think that this compromises security since the data will be transferred encrypted and
only the user has the encryption key.