Location Based Keys, Implementation of an encryption scheme
The purpose of a location-based security scheme for wireless sensor networks is to establish a solid base for secure authenticated communication that is strictly confined to a predefined area. In this thesis, an authentication and key exchange scheme allowing low-cost, resource-restricted sensors to benefit from authenticated location-aware encryption shall be presented. An extended scheme that allows location updates more frequently than key regeneration provides more fine-grained location constraints without compromising basic security qualities. A central authority called trust center (TC) is responsible for device location and key exchange. Communication between nodes within the network and additional per-device location restrictions can be imposed on a per-node basis without the TC necessarily knowing about it. The location is determined by an ultrasonic location system that effectively restricts the range of possible attack vectors to the predefined area and its close surrounding. It is possible to integrate nodes with various properties, such as sensors with fixed positions, mobile nodes without location constraints, or nodes that follow a predefined path. All characteristics are imposed by the TC, making easy extension with new modes possible by simply updating the TC.