@misc{cryptoeprint:2011:651,
author = {Kaoutar Elkhiyaoui and Erik-Oliver Blass and Refik Molva},
title = {CHECKER: On-site checking in RFID-based supply chains},
howpublished = {Cryptology ePrint Archive, Report 2011/651},
year = {2011},
note = {\url{http://eprint.iacr.org/}},
}
You will need the url.sty package (comes with most LaTeX installations) for the last line. Otherwise, remove the \url command.