Patent ID: 8046593

Claim:
A method for controlling access to a storage device, the method comprising; providing a storage device, wherein data stored on the storage device is capable of being accessed in accordance with a layered structure comprising a plurality of layers; associating at least a first key and a second key with a first layer and a second layer, respectively, of the plurality of layers of the layered structure; generating a final key indicative of a combination of at least the first and second keys associated with the first and second layers; controlling access to the storage device in accordance with a keyed transformation function and the final key; associating a key combining function with each layer having an associated key; in accordance with a predetermined sequence: for each associated key combining function having a next key combining function in the sequence, providing a respective key combining function output as an input to a next key combining function in the sequence; and for a final key combining function indicative of an associated key combining function, not having a next key combining function in the sequence, providing the final key, indicative of an output of the final key combining function, to the keyed transformation function; and performing one of: providing to the storage device, data transformed with the keyed transformation function in accordance with the final key; and transforming, with the keyed transformation function in accordance with the final key, data received from the storage device.