Cryptology ePrint Archive: BibTeX Citation of Report 2001/007

@misc{cryptoeprint:2001:007,
    author = {Ron RIvest & Robert Silverman},
    title = {Are 'Strong' Primes Needed for RSA},
    howpublished = {Cryptology ePrint Archive, Report 2001/007},
    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.