Supporting high levels of security in wireless networks is a challenging issue because of the specific problems this environment poses; the provided security by small mobile systems, such as PDAs and mobile phones, is often restricted by their limited battery power and their limited processing power. Driven by these restrictions, the designer will have to decide whether to implement the wireless network security schemes in software or to add special purpose hardware units to the system, executing those CPU intensive tasks. This paper demonstrates and compares the Hardware and Software implementations of a number of widely used security applications employed in wireless networks. We measured the total energy consumption for each security algorithm when implemented in reconfigurable hardware devices and we compared it with the total energy consumption of the equivalent software applications. We demonstrate, that the hardware implementations on a state-of-the-art FPGA are significantly faster while they consume three orders of magnitude less power when compared with the software implementations executed on a state-of-the-art hard-core CPU which is embedded in the same FPGA device.