We develop the open source encryption software Cryptomator, with which files intended for the cloud on the computer or smartphone can be easily encrypted. This allows us to ensure verifiable confidentiality in any cloud storage. In addition to the normal apps, Cryptomator is available as a white label. Our cryptographic software libraries can also be integrated into systems that companies can use to make their cloud storage verifiably secure. Cryptomator received the CeBIT Innovation Award from the BMBF in 2016 for its combination of user-friendliness and openness.