Cryptology ePrint Archive: BibTeX Citation of Report 2011/062

@misc{cryptoeprint:2011:062,
    author = {Swapnoneel Roy and Amlan K Das and Yu Li},
    title = {Cryptanalysis and Security Enhancement of an Advanced Authentication Scheme using Smart Cards, and a Key Agreement Scheme for Two-Party Communication},
    howpublished = {Cryptology ePrint Archive, Report 2011/062},
    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.