Cryptology ePrint Archive: BibTeX Citation of Report 2015/605

@misc{cryptoeprint:2015:605,
    author = {Steven D. Galbraith and Ping Wang and Fangguo Zhang},
    title = {Computing Elliptic Curve Discrete Logarithms with Improved Baby-step Giant-step Algorithm},
    howpublished = {Cryptology ePrint Archive, Report 2015/605},
    year = {2015},
    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.