Cryptology ePrint Archive: BibTeX Citation of Report 2008/271

@misc{cryptoeprint:2008:271,
    author = {Somitra Kumar Sanadhya and Palash Sarkar},
    title = {A Combinatorial Analysis of Recent Attacks on Step Reduced SHA-2 Family},
    howpublished = {Cryptology ePrint Archive, Report 2008/271},
    year = {2008},
    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.