Cryptology ePrint Archive: BibTeX Citation of Report 2013/117

@misc{cryptoeprint:2013:117,
    author = {Namhun Koo and Gook Hwa Cho and Soonhak Kwon},
    title = {On r-th Root Extraction Algorithm in F_q For q=lr^s+1 (mod r^(s+1)) with 0 < l < r and Small s},
    howpublished = {Cryptology ePrint Archive, Report 2013/117},
    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.