The ETHOS™ method is used for securing trust based on the information exchanged between the different nodes of a sensor network. The initiative investigated various trust metrics and algorithms to define a set of trust metrics that use information entropy as the basis for calculating the reputation of particular nodes.
In this U.S. Air Force Research Laboratory (AFRL) – Wright-Patterson AFB funded effort KBSI developed an Entropy-Trust-Homology Operational Security (ETHOS™) method for securing trust that is based on the information exchanged between the different nodes of a sensor network. Trust entropy metrics are created based on both the patterns of information entropy flow between nodes and on usage behavior. Usage behavior includes both user behavior (user monitoring) as well as CPU behavior (process monitoring). Each node in the system creates a set of trust metrics that corresponds to the set of directly observable neighboring nodes. A trust metric that reflects the reputation of a particular node could then be calculated by the direct and indirect querying of nodes in the network.