Yingjiu Li, Ph.D.
Associate Professor
School of Information Systems
Singapore Management University
Singapore

Contents
 Introduction
 Time cost of cryptographic operations
 Time cost of communications
 Protocol classification and time cost
 Conclusion

Contents
 Introduction
 Time cost of cryptographic operations
 Time cost of communications
 Protocol classification and time cost
 Conclusion

Introduction
 Time cost for executing an authentication protocol consists of three parts
– Tr: time cost for cryptographic operations and looking up a database at a reader side
– Tt: time cost for cryptographic operations at a tag side
– Tc: time cost of communication between a reader and a tag
 Objective
– Provide a benchmark for protocol development

Introduction
 Development Environment
– Emulator: UHF DemoTag, IAIK, TU Graz, Austria
– Reader: CAEN WA828, Italy
 We focus on Tt and Tc
– Tr is negligible as compared with Tt and Tc
Atmega 128 microcontroller

Contents
 Introduction
 Time cost of cryptographic operations
 Time cost of communications
 Protocol classification and time cost
 Conclusion

Time cost of cryptographic operations
 Time cost for a DemoTag to run cryptographic operations:
– Hashing: MD5, SHA-1, SHA-256, SHA-512
– Crypto: AES-128, AES-192, AES-256
– Ultra-lightweight: PRESENT-80

Time cost of cryptographic operations
 Time cost for a DemoTag to run cryptographic operations:
– Hashing: MD5, SHA-1, SHA-256, SHA-512
– Crypto: AES-128, AES-192, AES-256
– Ultra-lightweight: PRESENT-80

Contents
 Introduction
 Time cost of cryptographic operations
 Time cost of communications
 Protocol classification and time cost
 Conclusion

Time cost of communications
 Time cost of communications
– Tag-to-tag Read/Write operations
• Read: 0007ms / 16-bit word
• Write: 16.7ms / 16-bit word
– Reader-to-tag Read/Write operations

Contents
 Introduction
 Time cost of cryptographic operations
 Time cost of communications
 Protocol classification and time cost
 Conclusion

Protocol classification and time cost
 Four types of authentication protocols
– RAO: reader authentication only
• A reader authenticates its legitimacy to a tag
– TAO: tag authentication only
• A tag authenticates its legitimacy to a reader
– TRA: tag-then-reader authentication
• A tag authenticates its legitimacy to a reader and then the reader authenticates its legitimacy to the tag
– RTA: reader-then-tag authentication
• A reader authenticates its legitimacy to a tag and then the tag authenticates its legitimacy to the reader

Protocol classification and time cost
 Four types of authentication protocols
– Different types of protocols have different numbers of rounds of communications between a reader and a tag
 Communication time Tc takes the major time cost for executing a protocol, as shown in the figure in the next slide

Protocol classification and time cost
 Communication time Tc takes the major time cost for executing a protocol, as shown in the figure

Contents
 Introduction
 Time cost of cryptographic operations
 Time cost of communications
 Protocol classification and time cost
 Conclusion

Conclusion
 We have conducted pioneering study for time cost evaluation of RFID authentication protocols
 Future work
– Conduct some other asymmetric cryptographic operations like ECC, RSA, etc
– Conduct experiments on WISP tag platform

Question?