Cryptology ePrint Archive: BibTeX Citation of Report 2009/346

@misc{cryptoeprint:2009:346,
    author = {Wenling Wu  and  Lei Zhang  and  Liting Zhang  and  Wentao Zhang},
    title = {Security Analysis of the GF-NLFSR Structure and Four-Cell Block Cipher},
    howpublished = {Cryptology ePrint Archive, Report 2009/346},
    year = {2009},
    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.