A rear blade mounting apparatus for a bulldozer. The method includes generating indexes from the encrypted database, each index identifying records of the encrypted database associated with a range of data for at least one field stored in the records of the encrypted database, and generating index metadata associated with each index, the index metadata indicating the range of data identified by the associated index. The dielectric layer of present invention provides a first layer dielectric having a low deposition rate as a first step, and an efficiently formed second dielectric layer as a second completing step.