Cryptology ePrint Archive: BibTeX Citation of Report 2012/571

@misc{cryptoeprint:2012:571,
    author = {Changyong Peng and Chuangying zhu and Yuefei Zhu and Fei Kang},
    title = {Improved side channel attack on the block cipher NOEKEON},
    howpublished = {Cryptology ePrint Archive, Report 2012/571},
    year = {2012},
    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.