Computer security and privacy concerns have become a priority for our nation. A traditional approach is to develop strong and intelligent virus and intrusion detection programs. Although this approach is important, we believe this approach will never really put these concerns to rest. A more promising approach for running security and privacy sensitive programs is to be able to run them with guaranteed confidentiality and integrity in spite of a computing environment containing malware. We start with the difficulty of defining privacy and a review of some existing definitions. We continue with different approaches to run programs securely in an insecure environment. This includes white listing and process isolation techniques.