Cryptology ePrint Archive: BibTeX Citation of Report 2012/206

@misc{cryptoeprint:2012:206,
    author = {Shuang Wu and Dengguo Feng and Wenling Wu and Jian Guo and Le Dong and Jian Zou},
    title = {(Pseudo) Preimage Attack on Round-Reduced Gr{\o}stl Hash Function and Others (Extended Version)},
    howpublished = {Cryptology ePrint Archive, Report 2012/206},
    year = {2012},
    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.