Cryptology ePrint Archive: BibTeX Citation of Report 2013/382

@misc{cryptoeprint:2013:382,
    author = {Yevgeniy Dodis and Thomas Ristenpart and John Steinberger and Stefano Tessaro},
    title = {To Hash or Not to Hash Again? (In)differentiability Results for H^2 and HMAC},
    howpublished = {Cryptology ePrint Archive, Report 2013/382},
    year = {2013},
    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.