Cryptology ePrint Archive: BibTeX Citation of Report 2015/075

@misc{cryptoeprint:2015:075,
    author = {Jian Guo and Yu Sasaki and Lei Wang and Meiqin Wang and Long Wen},
    title = {Equivalent Key Recovery Attacks against HMAC and NMAC with Whirlpool Reduced to 7 Rounds},
    howpublished = {Cryptology ePrint Archive, Report 2015/075},
    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.