Capabilities and Encryption: The Ultimate Defense Against Security Attacks ?

Abstract

Capability-based addressing is an attractive mechanism to control access to information in an object-oriented system. Several capability-based systems have been built in the past, but most of them proved to be unsatisfactory because they suffered from severe performance penalties due to a number of implementation problems. In the MONADS-PC these problems have been solved by providing dedicated architectural support for a two-level capability scheme which is used to efficiently address and protect segments in its large uniform virtual memory and to control access to the semantic operations of major objects. Although this organization has many advantages for protecting information within a MONADS PC system, it is not sufficient to cope with the security attacks outside its sphere of control, such as physically copying software from removable storage devices or intercepting insecure communication lines in a network of computers. One way to avoid such security violations is to use encryption techniques. The focus of our research is to investigate the suitability of different encryption techniques in a MONADS environment. We discuss the issues involved in using encryption in conjunction with capabilities and postulate that both methods are necessary to provide a high degree of system security.