Cryptology ePrint Archive: BibTeX Citation of Report 2014/939

@misc{cryptoeprint:2014:939,
    author = {Gaurav Tiwari and Amit K. Awasthi and Neha Shukla},
    title = {Security Analysis of an Authentication Scheme Using Smart Cards},
    howpublished = {Cryptology ePrint Archive, Report 2014/939},
    year = {2014},
    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.