Patent ID: 8812442

Claim:
A system comprising: one or more processors; and a memory coupled to the one or more processors, wherein the memory stores program instructions executable by the one or more processors to: store user account data, wherein the user account data comprises information identifying convergently encrypted portions of data associated with a plurality of user accounts; prevent storage of duplicate copies of the convergently encrypted portions of data on a storage server, wherein preventing the storage of duplicate copies comprises determining whether a first signature is present in a signature index, wherein the signature index comprises signatures for convergently encrypted portions of data stored on the storage server, and the first signature is associated with a first convergently encrypted portion of data, storing the first convergently encrypted portion of data on the storage server, if the determining indicates that the first signature is absent from the signature index, refraining from storing the first convergently encrypted portion of data on the storage server, if the determining indicates that the first signature is present in the signature index; and update the signature index in response to the determining.