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Toward Practical Public Key Anti-Counterfeiting for Low-Cost EPC Tags. Alex Arbit , Avishai Wool, Yossi Oren, IEEE RFID April 2011. Outline. Anti-counterfeiting for RFID Cryptographic anti-counterfeiting Lab system setup WIPR protocol flow Implementation results Optimizations
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Toward Practical Public Key Anti-Counterfeiting for Low-Cost EPC Tags Alex Arbit, Avishai Wool, Yossi Oren, IEEE RFID April 2011
Outline • Anti-counterfeiting for RFID • Cryptographic anti-counterfeiting • Lab system setup • WIPR protocol flow • Implementation results • Optimizations • Summary & Future work
RFID EPC Supply chain • Counterfeiting is considered one of the greatest treats to the world’s economy • Electronic Product Code (EPC) is designed to guarantee uniqueness of every RFID Tag in Supply Chain • Problem: • Standard RFID EPC-based supply chain is generally unprotected and may become an easy target for the adversary
RFID Tags Anti-counterfeiting methods • Unique ID (EPC) • Unencrypted value – an easy prey for adversary! • A world-wide readers network database to trace compromised tag IDs (track-and-trace) • Essential cooperativeness of all supply chains • Loss of information privacy • Cryptographic solution • Asymmetric solution – Public key on Tag • Strong system protection – “breaking” one Tag doesn’t compromise the supply chain • Was considered not feasible for RFID chain due to high resource consumption on tag side and long execution times!
Cryptographic anti-counterfeiting protocol • Non-secret Public key (Tag, reader) • Private key (Reader only)
Asymmetric cryptographic approach • Tag bears only a partial (public) key -> can only encrypt messages • System not compromised even if a certain tag is • Reader possesses both key parts -> can encrypt and decrypt • Only one private key is required for entire chain • No need for a constant link to a central server
A system view of the suggested public-key based anti-counterfeiting system • Only Tag Integrator possesses all encryption and decryption keys • Tag manufacturer has no signing key • Unable to create arbitrary signed TIDs not from Integrator’s list • Reader has private decryption key but no signing key • Can only verify tags but unable to forge new ones • System can operate completely offline once keys are delivered
IAIK Demotag • EPC C1G2 fully compliant UHF tag • ATMega128 AVR controller • Integral 128kB Flash, 4kB SRAM • 16MHz crystal oscillator • Communication interfaces • JTAG • UART • RFID Analog Front End
Experimental System Setup • IAIK UHF Demotag with a WIPR algorithm mounted on it • CAEN RFID EPC1G2 Reader with MATLAB SCA toolkit • 2 PC Workstations
Full WIPR Protocol flow • Seamless protocol integration with standard EPC Class I Generation II commands
Y (ms) Implementation results – message encryption time as f(heap size) X (bytes) • Message encryption time shortened from initial 7 seconds down to 180 milliseconds using optimizations! • Will be checked on existing ASIC implementation for the same dramatic effect of RAM usage on performance
Response time as afunction of block read size • Reader-tag maximum wireless link speed 15kbps • After each data transaction reader “shuts down” the link – inefficient reader implementation slows the link down • Reading out large chunks of data ensures fastest response time
Response time as afunction of block read size – cont. • Reading out large chunks of data ensures fastest response time
Optimizations Total link time • Total system’s performance further improved from 840ms to 265ms with full link pipelining
Summary • A full strength Public key Crypto system is implemented on standard EPC C1 G2 Tag for RFID supply chain! • RAM usage presents a resource vs. message encrypt time latencytrade-off. • A better use of air interface by the reader side squeeze the total execution time down to 0.265s for full pipelining. • System designed for fully off-line operation can be further strengthened by use of standard reader track-and-trace with no additional cost on Tag side .
Future Work • Adding a small amount of RAM to existing ASIC implementation to compare performances and benchmarking • Integrate suggested anti-counterfeiting solution with current EPC C1G2 tag chips • Work with other reader vendors to see if they handle a standard EPC Class I Generation II more efficiently
Thank You! תודה רבה!