Data security and energy aware communication are key aspects in design of modern ad-hoc networks. In this paper, the authors investigate issues associated with the development of secure IEEE 802.15.4 based Wireless Sensor Networks (WSNs) - a special type of ad hoc networks. They focus on energy aware security architectures and protocols for use in WSNs. To give the motivation behind energy efficient secure networks, first, the security requirements of wireless sensor networks are presented and the relationships between network security and network lifetime limited by often in-sufficient resources of network nodes are explained. Second, a short literature survey of energy aware security solutions for use in WSNs is presented.