Patent ID: 8256010

Claim:
A method for providing off-line access to a data item, the method comprising: providing graph information to a recipient, the graph information including: node structure information which describes at least part of a node structure provided by one or more access graphs; label information which provides labels associated with a set of nodes in the node structure; marker information which provides markers associated with a set of edges connecting individual nodes from the set of nodes in the node structure; and key information which provides a set of keys that entitle the recipient to access at least part of the node structure; providing the data item to the recipient, the data item being protected using a content key; generating another marker and including the another marker in linking information, wherein the linking information associates the data item with the node structure as another node of the node structure representing the data item, the linking information associating the data item with at least a first node of the set of nodes in the node structure and a second node of the set of nodes in the node structure, and providing the linking information to the recipient, wherein generating the another marker comprises: applying one or more mathematical or logical operations to: the content key that protects the data item; a first key from the set of keys that is associated with the first node; a second key from the set of keys that is associated with the second node; and an individual label that is associated with the data item, the individual label associated with the data item being different than the content key that protects the data item, and applying a hash function to the first key, the second key, and the label, wherein the graph information and the linking information allow the recipient to access the content key and decrypt the data item using the content key, and at least the generating the another marker is performed by a computing device.