Cryptology ePrint Archive: BibTeX Citation of Report 2006/016

@misc{cryptoeprint:2006:016,
    author = {Yusuke Naito and Yu Sasaki and Takeshi Shimoyama and Jun Yajima and Noboru Kunihiro and Kazuo Ohta},
    title = {Message Modification for Step 21-23 on SHA-0},
    howpublished = {Cryptology ePrint Archive, Report 2006/016},
    year = {2006},
    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.