Cryptology ePrint Archive: BibTeX Citation of Report 2008/048

@misc{cryptoeprint:2008:048,
    author = {Donghoon Chang,  Jaechul Sung, Seokhie Hong and Sangjin Lee},
    title = {Improved Cryptanalysis of APOP-MD4 and NMAC-MD4 using New Differential Paths},
    howpublished = {Cryptology ePrint Archive, Report 2008/048},
    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.