Energy Comparison of AES and SHA-1 for Ubiquitous Computing

• Published in: Emerging Directions in Embedded and Ubiquitous Computing pp. 372 - 381
• Main Authors: Kaps, Jens-Peter, Sunar, Berk
• Format: Book Chapter Conference Proceeding
• Language: English
• Published: Berlin, Heidelberg Springer Berlin Heidelberg 2006; Springer
• Series: Lecture Notes in Computer Science
• Subjects: Advance Encryption Standard; Applied sciences; Block Cipher; Clock Cycle; Computer science; control theory; systems; Computer systems and distributed systems. User interface; Cryptography; Exact sciences and technology; Information, signal and communications theory; Memory and file management (including protection and security); Memory organisation. Data processing; Message Authentication Code; Signal and communications theory; Software; Telecommunications and information theory; Ubiquitous Computing; Pervasive computing; Energy consumption; Measurement sensor; Encryption; Low power; Distributed system; Energy savings; Low energy; Boarded computer; Identifier; Authentication; Hashing; Digital circuit; Wireless network; Radio networks; Cryptography; Resource management; Sensor array; Mobile computing; Radio communication; Radio frequency identification
• ISBN: 3540368507; 9783540368502
• ISSN: 0302-9743; 1611-3349
• DOI: 10.1007/11807964_38

Wireless sensor networks and Radio Frequency Identifiers are becoming mainstream applications of ubiquitous computing. They are slowly being integrated into our infrastructure and therefore must incorporate a certain level of security. However, both applications are severely resource constrained. Energy scavenger powered sensor nodes and current RFID tags provide only 20 μ W to 50 μ W of power to the digital component of their circuits. This makes complex cryptography a luxury. In this paper we present a novel ultra-low power SHA-1 design and an energy efficient ultra-low power AES design. Both consume less than 30 μ W of power and can therefore be used to provide the basic security services of encryption and authentication. Furthermore, we analyze their energy consumption based on the TinySec protocol and come to the somewhat surprising result, that SHA-1 based authentication and encryption is more energy efficient than using AES for payload sizes of 17 bytes or larger.