Cryptology ePrint Archive: BibTeX Citation of Report 2011/381

@misc{cryptoeprint:2011:381,
    author = {Yalin Chen1, Jue-Sam Chou2, Chi-Fong Lin3, Cheng-Lun Wu4},
    title = {A Novel RFID Authentication Protocol based on Elliptic Curve Cryptosystem },
    howpublished = {Cryptology ePrint Archive, Report 2011/381},
    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.