Cryptology ePrint Archive: BibTeX Citation of Report 2005/007

@misc{cryptoeprint:2005:007,
    author = {Hongjun Wu},
    title = {The Misuse of RC4 in Microsoft Word and Excel},
    howpublished = {Cryptology ePrint Archive, Report 2005/007},
    year = {2005},
    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.