Cryptography for Ultra-Low Power Devices

Motivation and Background

Ubiquitous computing describes the notion that computing devices will be everywhere: clothing, walls and floors of buildings, cars, the desert etc. Ubiquitous computing is becoming reality: RFIDs are currently being introduced into the supply chain. Wireless distributed sensor networks are already being used to monitor wildlife and to track military targets. Many more applications are being envisioned. For most of these applications some level of security is of utmost importance.

Providing security for ubiquitous computing provides special challenges. Common to all applications above is that the computing devices is that their power resources are severely limited. These are ultra-low power devices. The table below gives an overview of what ultra-low power means.

Application	Power Source	Power Range
Desktop Computer	Power Grid	150 W	-	500 W
Laptops	High Capacity Battery	10 W	-	120 W
Palm size devices, Cell Phones, Embedded Systems	Battery	100m W	-	10 W
Wireless Sensors	Tiny Batteries	1 mW	-	100 mW
Smart Dust, RFID	Energy Scavenging	1 μW	-	500 μW

Current wireless sensor nodes are powered by tiny batteries. We are already seeing a trend to use energy scavengers to power sensor nodes. Scavengers convert ambient heat, noise, vibration, or light to electrical power. Sensor nodes that are powered solely by scavengers are called self-powered. The fact, that the sensor node communicates wirelessly and has no battery makes them autonomous. This opens up a whole new range of applications. The nodes can be placed in locations that are later entirely inaccessible.

Our Research

Many research groups are working on developing wireless sensor nodes, RFIDs, etc. The links section below lists a few of the major groups. A handful of research groups are trying to tackle the security challenges. However, the common perception in the wireless sensor node and in the RFID communities is, that public key cryptography is not possible on these tiny devices. We set out to challenge this assumption. Our goal is to develop a suite of cryptographic functions for authentication, encryption, and integrity that is specifically tailored to the needs ultra-low power devices. This includes public key cryptography and secure hash functions. For this we are examining existing cryptographic algorithms and either find energy efficient ways to implement them, improve them, or we develop new algorithms.

Publications

These are only our publications about Cryptography for Ultra-Low Power Devices. For a complete list of the publications from the CRIS lab have a look at our publications page.

G. Gaubatz, J.-P. Kaps, and B. Sunar, Public key cryptography in sensor networks---revisited 1st European Workshop on Security in Ad-Hoc and Sensor Networks (ESAS 2004), 2004. (PDF)
K. Yüksel, J.-P. Kaps, and B. Sunar, "Universal Hash Functions for Emerging Ultra-Low-Power Networks" , Proceeding of The Communications Networks and Distributed Systems Modeling and Simulation Conference (CNDS), San Diego, CA, January, 2004. (PDF)
Kaan Yüksel "Universal Hashing for Ultra-Low-Power Cryptographic Hardware Applications", Master's Thesis, Worcester Polytechnic Institute, May 2004. (PDF)

Links to Other Research Groups

These links open in a new browser window. Neither WPI nor the CRIS lab are responsible for the content of these external web sites.

Smart Dust Autonomous sensing and communication in a cubic millimeter
TinyOs a component-based OS for the networked sensor regime
TinySec Link Layer Encryption for Tiny Devices
Pico Radio
UCLA Center for Embedded Network Sensing (CENS) (if this link returns an empty page try this link.)
Dust Inc.

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Last modified: Sep 22, 2006, 20:31 EDT