A cloud storage system supporting user agnostic encryption and deduplication of encrypted files is described. Further the cloud storage system enables users to share a file, a group of files, or an entire file system with other users without a user sending each file to the other users. The cloud storage system further allows a client device to minimize the utilization of bandwidth by determining whether the encrypted data to transfer is already present in the cloud storage system. Further the cloud storage system comprises mechanisms for a client device to inform the cloud storage system of which data is likely to be required in the future so that the cloud storage system can make that data available with less latency one the client device requests the data.