Cryptology ePrint Archive: BibTeX Citation of Report 2001/003

@misc{cryptoeprint:2001:003,
    author = {Antoine Joux and Kim Nguyen},
    title = {Separating Decision Diffie-Hellman from Diffie-Hellman in cryptographic groups},
    howpublished = {Cryptology ePrint Archive, Report 2001/003},
    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.