Summer 2004

Unless indicated otherwise, the CryptoSeminar is being held in the Atwater Kent building on the WPI Worcester campus. The Atwater Kent building is at the intersection of Salisbury Street and the extension of West Street (labeled "Private Way"). See directions to campus.

The talks are 30-45 minutes long and are open to everyone.

Refreshments are usually being served 15 minutes before the talk. There is no fee and no formal registration. If you are attending a Seminar for the first time, a short e-mail to Profs. Berk Sunar or Bill Martin, saying that you would like to attend, would be appreciated.

Public Key Cryptography in Sensor Networks -- Revisited

Gunnar Gaubatz, Cryptography and Information Security (CRIS) Laboratory, Worcester Polytechnic Institute (WPI)
Friday July 30, 2004, 3pm, Atwater Kent, WPI, Room 108

Abstract

The common perception of public key cryptography is that it is complex, slow and power hungry, and as such not at all suitable for use in ultra-low power environments like wireless sensor networks. It is therefore common practice to emulate the asymmetry of traditional public key based cryptographic services through a set of protocols using symmetric key based message authentication codes (MACs). Although the low computational complexity of MACs is advantageous, the protocol layer requires time synchronization between devices on the network and a significant amount of overhead for communication and temporary storage. The requirement for a general purpose CPU to implement these protocols as well as their complexity makes them prone to vulnerabilities and practically eliminates all the advantages of using symmetric key techniques in the first place.

In this talk we challenge the basic assumptions about public key cryptography in sensor networks which are based on a traditional software based approach. We propose a custom hardware assisted approach for which we claim that it makes public key cryptography feasible in such environments, provided we use the right selection of algorithms and associated parameters, careful optimization, and low-power design techniques.

In order to validate our claim, we present proof of concept implementations of two different algorithms -- Rabin's Scheme and NtruEncrypt -- and analyze their architecture and performance according to various established metrics like power consumption, area, delay, throughput, level of security and energy per bit. Our implementation of NtruEncrypt in ASIC standard cell logic uses no more than 3,000 gates, with an average power consumption of less than 20 uW. We envision that our public key core would be embedded into a light-weight sensor node architecture.

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Last modified: Monday, 10-Jan-2005 22:02:15 EST