Patent ID: 7930315

Claim:
A method by which clients connected to a network store a plurality of data entities, which comprise constituent data items, in a data repository that enforces retention requirements, the method comprising: storing data items in the data repository in response to storage requests sent over the network by clients of the data repository; determining a digital fingerprint from the contents of a data item; testing for whether the data item is stored in the repository by comparing the digital fingerprint of the data item to digital fingerprints of data items stored in the data repository; and assigning an expiration time to the data item, before which time the data repository prohibits both modification and deletion of the data item; wherein the expiration time assigned to the data item is finite; wherein a request sent over the network by a client of the data repository causes the expiration time to be assigned; wherein a location at which the data item is stored is determined, at least in part, by the digital fingerprint; wherein determining the location comprises choosing one of a plurality of disk drives or data servers or buildings or cities; wherein, once the expiration time has been assigned and as long as the expiration time has not yet passed, the client of the data repository can change the expiration time to be later but no action taken by the client can change the expiration time to be sooner than it is at the time of the action or cause the data item to be deleted from the data repository; and wherein after the expiration time has passed deletion of the data item is allowed.