Cryptology ePrint Archive: BibTeX Citation of Report 2001/070

@misc{cryptoeprint:2001:070,
    author = {Kenji Ohkuma and Hideo Shimizu and Fumihiko Sano and Shinichi Kawamura},
    title = {Security Assessment of Hierocrypt and Rijndael against the Differential and Linear Cryptanalysis (Extended Abstract)},
    howpublished = {Cryptology ePrint Archive, Report 2001/070},
    year = {2001},
    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.