Wireless sensor networks have been widely used in many surveillance applications. Due to the importance of sensor nodes in such applications, certain level of protection needs to be provided to them. We study the self protection problem for static wireless sensor networks in this paper. Self protection problem focuses on using sensor nodes to provide protection to themselves instead of the target objects or certain target area, so that the sensor nodes can resist the attacks targeting on them directly. A wireless sensor network is p-self-protected, if for any wireless sensor there are at least p active sensors that can monitor it. The problem finding minimum p-self-protection is NP-complete and no efficient self protection algorithms have been proposed. In this paper, we provide efficient centralized and distributed algorithms with constant approximation ratio for minimum p-selfprotection problem. In addition, we design efficient distributed algorithms to not only achieve p-self-protec...