411 Security in Wireless Sensor Networks with Mobile Codes Frantisek Zboril Jr. Brno University of Technology, Czech Republic Jan Horacek Brno University of Technology, Czech Republic Martin Drahansky Brno University of Technology, Czech Republic Petr Hanacek Brno University of Technology, Czech Republic Chapter 21 ABSTRACT Security of wireless sensor networks (WSN) relates in many aspects to security of distributed systems. On the first sight WSNs form a large distributed ad-hoc system with lot of tiny devices that sense some phenomena and communicate wirelessly. Due to some limitations, among which the energy consumption problem is the most important one, security issues could demand different solutions than those used in the area of ordinary distributed systems. In this chapter, the authors briefly introduce the hardware and software approach to WSN design first, and then they define the main security aspects in such systems. Then some security mechanisms are presented, and their connection to possible countermeasures of the identified risks is described. 1 INTRODUCTION Security of wireless sensor networks (WSN) relates in many aspects to security of distributed systems. On the first sight WSNs form a large distributed ad-hoc system with lot of tiny devices that sense some phenomena and communicate wirelessly. Due to some limitations, among which DOI: 10.4018/978-1-4666-0978-5.ch021 the energy consumption problem is the most im- portant one also the security issues could demand different solutions than these used in the area of ordinary distributed systems. In this chapter we briefly introduce the hardware and software ap- proach to WSN design first and then we define the main security aspects in such systems. Then some security mechanisms will be presented and their connection to possible countermeasures of the identified risks will be described. Copyright © 2012, IGI Global. Copying or distributing in print or electronic forms without written permission of IGI Global is prohibited.