1. A system, comprising: a first data storage service comprising a plurality of data storage devices and a first web service interface configured to receive web service requests transmitted to the first web service interface, the first data storage service being configured to process the web service requests transmitted to the first web service interface using the plurality of data storage devices; a second data storage service comprising a second web service interface, the second data storage service configured to operate as a proxy to the first data storage service by at least: receiving, to the second web service interface, a request from a requestor to store data; encrypting the data using a cryptographic key inaccessible to the first data storage service; transmitting the encrypted data to the first data storage service for persistent storage on behalf of the requestor; and maintain access to the cryptographic key while preventing access to the cryptographic key by the first data storage service.