Cryptology ePrint Archive: BibTeX Citation of Report 2012/406

@misc{cryptoeprint:2012:406,
    author = {*Jue-Sam Chou 1, Yalin Chen2, Chun-Hui Huang 3, Yu-Siang Huang4},
    title = {Comments on four multi-server authentication protocols using smart card},
    howpublished = {Cryptology ePrint Archive, Report 2012/406},
    year = {2012},
    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.