Abstract: A method and system for prioritizing, securing, and reducing the amount of data transmitted and stored during the creation of a backup copy of file data. Sectors in which changes have been made are identified as are the actual changes made to the sectors. Only the actual changes within each changed sector, along with the HCS number and a byte offset identifying the location within the sector at which the changes occur, are transmitted to the backup site. Files that are to be transmitted to the backup site are prioritized according to ratings based on predetermined criteria. Higher rated files are transmitted to the backup site prior to lower rated files. The files that are to be transmitted to the backup site are encoded and double encrypted. All instances of predetermined client-specific data elements within each file are identified and replaced by a corresponding code prior to encryption.