Patent ID: 7552328

Claim:
A system comprising a trusted computing platform, one or more logically protected computing environments and a filesystem comprising a plurality of files and links defining access paths between said files, the system being arranged to load onto said trusted computing platform a predetermined security policy including a plurality of security rules in respect of one or more of said logically protected computing environments and/or said files, the system being further arranged to: (1) determine that first and second security rules apply to a specified file or set of files, (2) determine the complete set of files, or fileset, to which each of said first and second security rules applies, (3) determine if the fileset of said first security rule is a complete subset of the fileset of said second security rule, and if so, a. applying said first security rule to said specified file or set of files, and otherwise, b. selecting one of said first and second security rules on the basis of another attribute thereof, and applying the selected security rule to said specified file or set of files.