Date Added: Oct 2012
Wireless sensor networks have been widely deployed in many applications, e.g., military field surveillance, health care, environment monitor, accident report, etc. Each sensor detects a target within its radio range, performs simple computations, and communicates with other sensors. Generally, sensors are constrained in battery power, communication, and computation capability; therefore, reducing the power consumption is a critical concern for a WSN. Unfortunately, an adversary has the ability to capture cluster heads. It would cause the compromise of the whole cluster; these schemes restrict the data type of aggregation or cause extra transmission overhead.