Abstract. In this paper we introduce ContikiSec, a secure network layer for wireless sensor networks, designed for the Contiki Operating System. ContikiSec has a configurable design, providing three security modes starting from confidentiality and integrity, and expanding to confidentiality, authentication, and integrity. ContikiSec has been designed to balance low energy consumption and security while conforming to a small memory footprint. Our design was based on performance evaluation of existing security primitives and is part of the contribution of this paper. Our evaluation was performed in the Modular Sensor Board hardware platform for wireless sensor networks, running Contiki. Contiki is an open source, highly portable operating system for wireless sensor networks (WSN) that is widely used in WSNs.

Starting with the implantable pacemaker, microelectronic implants have been around for more than 50 years. A plethora of commercial and research-oriented devices have been developed so far for a wide range of biomedical applications. In view of an envisioned expanding implant market in the years to come, our ongoing research work is focusing on the specification and design of a novel biomedical microprocessor core, carefully tailored to a large subset of existing and future biomedical applications. Towards this end, we have taken steps in identifying various tasks commonly required by such applications and profiling their behavior and requirements. One such task is decryption of incoming commands to an implant and encryption of outgoing (telemetered) biological data. Secure bidirectional information relaying in implants has been largely overlooked so far although protection of personal (biological) data is very crucial. In this context, we evaluate a large number of symmetric (block) ciphers in terms of various metrics: average and peak power consumption, total energy budget, encryption rate and efficiency, program-code size and security level. For our study we use XTREM, a performance and power simulator for Intel’s XScale embedded processor. Findings indicate the best-performing ciphers across all metrics to be MISTY1 (scores high in all imposed metrics), IDEA and RC6 (both present in 4 out of 5 metrics). Further profiling of MISTY1 indicates a clear dominance of load/store, move and logicoperation instructions which gives us explicit directions for designing the architecture of our novel processor.

Abstract—With the increased application of wireless sensor networks (WSNs) to military, commercial, and home environments, securing the data in the network has become a critical issue. Several security mechanisms, such as TinySec, have been introduced to address the need for security in WSNs. The cost of security, however, still mostly remains an unknown variable. To provide a better understanding of this cost we have studied three aspects of WSNs security: encryption algorithms, modes of operation for block ciphers, and message authentication algorithms. We have measured and compared their memory and energy consumption on both MicaZ and TelosB sensor motes. The results of our experiments provide insight into the suitability of different security algorithms for use in WSN environments and could be used by WSN designers to construct the security architecture of their systems in a way that both satisfies the requirements of the application and reasonably uses the constrained sensor resources. I.