The growing number of instances of breaches in information security in the last few years has created a compelling case for efforts towards secure electronic systems. Embedded systems, which will be ubiquitously used to capture, store, manipulate, and access data of a sensitive nature, pose several unique and interesting security challenges. Security has been the subject of intensive research in the areas of cryptography, computing, and networking. However, despite these efforts, security is often mis-construed by designers as the hardware or software implementation of specific cryptographic algorithms and security protocols. In reality, it is an entirely new metric that designers should consider throughout the design process, along with other metrics such as cost, performance, and power. This paper is intended to introduce embedded system designers and design tool developers to the challenges involved in designing

This paper investigates performance and energy characteristics of software algorithms for long integer arithmetic. We analyze and compare the number of RISC-like processor instructions (e.g. single-precision multiplication, addition, load, and store instructions) required for the execution of different algorithms such as Schoolbook multiplication, Karatsuba and Comba multiplication, as well as Montgomery reduction. Our analysis shows that a combination of Karatsuba-Comba multiplication and Montgomery reduction (the so-called KCM method) allows to achieve better performance than other algorithms for modular multiplication. Furthermore, we present a simple model to compare the energy-efficiency of arithmetic algorithms. This model considers the clock cycles and average current consumption of the base instructions to estimate the overall amount of energy consumed during the execution of an algorithm. Our experiments, conducted on a StrongARM SA-1100 processor, indicate that a 1024-bit KCM multiplication consumes about 22% less energy than other modular multiplication techniques.

Minimizing power consumption is crucial in battery power-limited secure wireless mobile networks. In this paper, we (a) introduce a hardware/software set-up to measure the battery power consumption of encryption algorithms through real-life experimentation, (b) based on the profiled data, propose mathematical models to capture the relationships between power consumption and security, and (c) formulate and solve security maximization subject to power constraints. Numerical results are presented to illustrate the gains that can be achieved in using solutions of the proposed security maximization problems subject to power constraints.

Encryption algorithms can be used to help secure wireless communications, but securing data also consumes resources. The goal of this research is to provide users or system developers of personal digital assistants and applications with the associated time and energy costs of using specific encryption algorithms. Four block ciphers (RC2, Blowfish, XTEA, and AES) were considered. The experiments included encryption and decryption tasks with different cipher and file size combinations. The resource impact of the block ciphers were evaluated using the latency, throughput, energylatency product, and throughput/energy ratio metrics. We found that RC2 encrypts faster and uses less energy than XTEA, followed by AES. The Blowfish cipher is a fast encryption algorithm, but the size of the plaintext affects its encryption speed and energy consumption. Faster algorithms seem to be more energy efficient because of differences in speed rather than differences in power consumption levels while encrypting. 1.

Digital watermarking is a process that embeds an imperceptible signature or watermark in a digital file containing audio, image, text or video data. The watermark is later used to authenticate the data file and for tamper detection. It is particularly valuable in the use and exchange of digital media such as audio and video on emerging handheld devices. However, watermarking is computationally expensive and adds to the drain of the available energy in handheld devices. We present an approach in which we partition the watermarking embedding and extraction algorithms and migrate some tasks to a proxy server. This leads to a lower energy consumption on the handheld without compromising the security of the watermarking process. Our results show that executing watermarking partitioned between the proxy and the handheld reduces the total energy consumed by 80% over running it only on the handheld and improves performance by over two orders of magnitude.

Group communication has become an important component in wireless networks. In this paper, we focus on the environments in which multiple groups coexist in the system, and both intra and inter group multicast traffic must be protected by secret keys. We propose a mechanism that integrates polynomials with flat tables to achieve personal key share distribution and efficient key refreshment during group changes. The proposed mechanism distributes keys via true broadcast. The contributions of the research include: (1) By switching from asymmetric algorithms to symmetric encryption methods, the proposed mechanism avoids heavy computation, and improves the processing efficiency of multicast traffic and the power usage at the wireless nodes. The group managers do not have to generate public-private key pairs when the group member changes. (2) It becomes more difficult for an attacker to impersonate another node since personal key shares are adopted. The additional storage overhead at the wireless nodes and the increased broadcast traffic during key refreshment are justified. In addition, we describe techniques to improve the robustness of the proposed mechanism under the complicated scenarios such as collusive attacks and batch group member changes.

Many modern electronic systems—including personal computers, PDAs, cell phones, network routers, smart cards, and networked sensors to name a few—need to access, store, manipulate, or communicate sensitive information, making security a serious concern in their design. Embedded systems, which account for a wide range of products from the electronics, semiconductor, telecommunications, and networking industries, face some of the most demanding security concerns—on the one hand, they are often highly resource constrained, while on the other hand, they frequently need to operate in physically insecure environments. Security has been the subject of intensive research in the context of general-purpose computing and communications systems. However, security is often misconstrued by embedded system designers as the addition of features, such as specific cryptographic algorithms and security protocols, to the system. In reality, it is a new dimension that designers should consider throughout the design process, along with other metrics such as cost, performance, and power. The challenges unique to embedded systems require new approaches to security covering all aspects of embedded system design from architecture to implementation. Security processing, which refers to the computations that must be performed in a system for the purpose of security, can

Abstract We propose a set of security provisions for node to base station communication in wireless sensor networks. It supports standard security requirements, viz. authentication of the origin of data and confidentiality of data. Additionally we use key evolution to achieve forward security which is of particular importance in the face of node capture attacks. As a bonus we obtain implicit weak freshness without message expansion. We take the typical resource constraints of wireless sensor networks into account. The security provisions can be superimposed on several communication models, such as the epidemic communication model. 1

Mobile wireless network security has emerged as an important topic of research recently. It is well known that security approaches based on encryption play a major role in this domain. One major hurdle in providing information security in mobile wireless devices is the limited battery power. The pace of advancements in battery

For some classes of embedded devices or sensors the ubiquotous, well researched methods and frameworks for key establishment cannot be deployed because of device constraints. This paper examines and motivates these limitations, which also forms the design criteria for key establishment protocols related to this class of devices. A collection of existing methods are presented, and the paper is concluded with some new key establishment ideas, especially targeted for constrained, mobile devices, rather that only sensor networks. 1