Failure Models for Intrusion Tolerance

Speaker: Timo Warns

Abstract

Intrusion tolerance combines the fields of fault tolerance and security to prevent adverse consequences in the presence of intrusions. Such a context yields several challenges for the application of fault tolerance approaches. Fault-tolerant algorithms were developed with the threshold model under the assumption of independent failures. However, this assumption is not valid in the presence of adversaries anymore. Within the talk, we briefly present current failure models that cover dependent failures and, therefore, provide an improved assumption coverage. Furthermore, we show that they are strictly stronger than the common threshold model and equivalent among each other wrt. the solvability of problems. Finally, we introduce a new model for directed dependent failures and show that this model is strictly stronger than the models known so far.