An object-oriented view of fragmented data processing for fault and intrusion tolerance in distributed systems

Abstract

This paper describes a technique, called Object-Oriented Fragmented Data Processing, for jointly improving the reliability and security with which distributed computing systems process sensitive information. The technique protects the information contained in, and the processing performed by, a given object by first fragmenting the object into the subsidiary objects of which it is composed. It then relies on the (i) the correct execution of a majority of a set of copies of these subsidiary objects, and (ii) the reliable storage of a majority of a set of copies of each of these subsidiary objects, having distributed the subsidiary objects widely across a number of computers in a distributed computing system. The intent is to impede intruders and to tolerate faults, and involves ensuring that an isolated subsidiary object is not significant, due to the lack of information it would provide to a potential intruder. This technique can be applied to application objects and/or to the objects used in the implementation of the basic object-oriented system. The paper illustrates the technique using a detailed example, of an “electronic diary”, that has been designed using Eiffel, and experimented with using the DELTA-4 Support Environment.