Cryptology ePrint Archive: BibTeX Citation of Report 2011/704

@misc{cryptoeprint:2011:704,
    author = {Masoumeh Safkhani  and Nasour Bagheri  and Majid Naderi},
    title = {Security Analysis of a PUF based RFID Authentication Protocol},
    howpublished = {Cryptology ePrint Archive, Report 2011/704},
    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.