Cryptology ePrint Archive: BibTeX Citation of Report 2014/643

@misc{cryptoeprint:2014:643,
    author = {Ashok Kumar Das},
    title = {On the Security of `An Efficient Biometric Authentication Protocol for Wireless Sensor Networks'},
    howpublished = {Cryptology ePrint Archive, Report 2014/643},
    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.