Cryptology ePrint Archive: BibTeX Citation of Report 2011/160

@misc{cryptoeprint:2011:160,
    author = {Mohamed Ahmed Abdelraheem and Céline Blondeau and María Naya-Plasencia and Marion Videau and Erik Zenner},
    title = {Cryptanalysis of ARMADILLO2},
    howpublished = {Cryptology ePrint Archive, Report 2011/160},
    year = {2011},
    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.