Patent ID: 7874013

Claim:
A computer-implemented method comprising: evaluating, by a computer system, a user query against a plurality of documents having sub-document level security control using a data structure, wherein said data structure includes a plurality of indexes, wherein each of said plurality of indexes belongs to a different one of a plurality of security access levels, wherein each of said plurality of indexes belonging to said plurality of security access levels is encrypted using a different encryption key, wherein different portions of the plurality of documents are assigned different ones of the plurality of security access levels, and wherein each of the portions is indexed by the one of the plurality of indexes belonging to the one of the plurality of security levels assigned to that portion, wherein said sub-document level security control restricts access to the portions of said plurality of documents through use of the different ones of the plurality of indexes belonging to the different ones of said plurality of security access levels; determining, by the computer system, a security access level for said user; and providing, by the computer system, a result for said user query based on said security access level for said user and said sub-document level security control.