1. A method of providing a high assurance service to an application program running on an operating system in a partition in a virtualized computer system, comprising: providing the high assurance service in a local secure service partition separate from said partition of said operating system; calling said high assurance service to process data when said high assurance service is requested by said application program; said local secure service partition certifying the results of said data processing by said high assurance process using a trusted key that uniquely identifies said local secure service partition.