@misc{cryptoeprint:2009:481,
author = {Erik-Oliver Blass and Kaoutar Elkhiyaoui and Refik Molva},
title = {PPS: Privacy Preserving Statistics using RFID Tags},
howpublished = {Cryptology ePrint Archive, Report 2009/481},
year = {2009},
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.