Cryptology ePrint Archive: BibTeX Citation of Report 2007/207

@misc{cryptoeprint:2007:207,
    author = {Claude Carlet, Khoongming Khoo, Chu-Wee Lim, Chuan-Wen Loe},
    title = {On an Improved Correlation Analysis of Stream Ciphers Using Muti-Output Boolean Functions and the Related Generalized Notion of Nonlinearity},
    howpublished = {Cryptology ePrint Archive, Report 2007/207},
    year = {2007},
    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.