Patent ID: 7702905

Claim:
A method for encrypted data transmission in a sensor network wherein the sensor network comprises a multitude of sensor nodes and at least one sink node and wherein the data traffic within the sensor network converges in the sink node, comprising: selecting from a set K, a subset K* of keys k, and storing the selected subset K* in the individual sensor nodes together with corresponding key identifiers IDk; each of the sensor nodes in a set of the sensor nodes selecting from the subset K* a random set of keys k1, . . . , kr, the set of sensor nodes being within transmission range of the sink node and within a first hop of the sink node; each of the sensor nodes in the set of sensor nodes respectively storing either exactly one key ki of the selected set of keys k1, . . . , kr and erasing all the rest of the stored keys k of subset K*, or erasing all keys k of subset K*; each of the sensor nodes in the set of sensor nodes sending a list of the key identifiers IDk1, . . . , IDkr corresponding to its selected set of keys k1, . . . , kr, the sent list of key identifiers being received by the sensor nodes in a further set of the sensor nodes that are farther from the sink node than the set of sensor nodes; each of the sensor nodes in the further set of the sensor nodes receiving the list of key identifiers IDk1, . . . , IDkr, respectively storing either exactly one key ki of the set of keys k1, . . . , kr corresponding to the list and erasing all the rest of the stored keys k of subset K*, or erasing all the keys k of subset K*; and repeating the previous two steps with yet further sets of sensor nodes that are located farther away from the sink node until the farthest sensor node of the network is reached, and by doing so, the sensor network is divided into areas, denoted routable regions, in such a way that all the sensor nodes within one area have stored either exactly one or no key ki from the corresponding original selectable set of keys k1, . . . , kr.