Cryptology ePrint Archive: BibTeX Citation of Report 2005/039

@misc{cryptoeprint:2005:039,
    author = {Joan Daemen and Gilles Van Assche},
    title = {Distinguishing Stream Ciphers with Convolutional Filters},
    howpublished = {Cryptology ePrint Archive, Report 2005/039},
    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.