Cryptology ePrint Archive: BibTeX Citation of Report 2013/178

@misc{cryptoeprint:2013:178,
    author = {Mohammad Ali Orumiehchiha and Josef Pieprzyk and  Elham Shakour and Ron Steinfeld},
    title = {Cryptanalysis of RC4(n,m) Stream Cipher},
    howpublished = {Cryptology ePrint Archive, Report 2013/178},
    year = {2013},
    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.