Cryptology ePrint Archive: BibTeX Citation of Report 2004/019

@misc{cryptoeprint:2004:019,
    author = {Tetsu Iwata and Tadayoshi Kohno},
    title = {New Security Proofs for the 3GPP Confidentiality and Integrity Algorithms},
    howpublished = {Cryptology ePrint Archive, Report 2004/019},
    year = {2004},
    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.