Patent ID: 8156563

Claim:
A method for controlling use of and/or access to a content file using a rights object navigation file and one or more rights object storage files, wherein each of the entries in the rights object navigation file corresponds to a location for storing one of a plurality of rights objects in the one or more rights object storage files, comprising: performing the following in a memory device configured to communicate with a host device: opening the rights object navigation file; finding in the rights object navigation file an entry which does not correspond to a location of a valid rights object in the one or more rights object storage files; obtaining a rights object; controlling use of and/or access to the content file in accordance with the rights object; and storing the rights object at the location in the one of the rights object storage file(s) corresponding to the entry; wherein the one or more rights object storage files comprises a plurality of rights object storage files each having m entries, wherein the rights object navigation information comprises an index which has a different value for each entry in the rights object navigation file, said method further comprising finding the location in the one or more rights object storage files corresponding to the entry for storing the rights object, wherein said finding includes dividing the index by m to obtain a quotient, to obtain an integer equal to the integer portion of the quotient, and an offset equal to the remainder portion of the quotient.