Does anyone here have experience with Tresorit? [1] They claim to offer something similar in terms of secure sharing, but with zero-knowledge encryption, i.e. without storing keys on the server. [2]
Trouble is that the service seems very new, so not many reviews exist. The client being closed-source doesn't help, and I'm not in a position to evaluate their bounty program.
[1] https://tresorit.com/features
[2] https://tresorit.com/files/encrypted-link-whitepaper.pdf