Cryptology ePrint Archive: BibTeX Citation of Report 2009/206

@misc{cryptoeprint:2009:206,
    author = {Bernhard Jungk, Steffen Reith, Juergen Apfelbeck},
    title = {On Optimized FPGA Implementations of the SHA-3 Candidate Groestl},
    howpublished = {Cryptology ePrint Archive, Report 2009/206},
    year = {2009},
    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.