Cryptology ePrint Archive: BibTeX Citation of Report 2015/258

@misc{cryptoeprint:2015:258,
    author = {Siang Meng Sim and Khoongming Khoo and Fr\'ed\'erique Oggier and Thomas Peyrin},
    title = {Lightweight MDS Involution Matrices},
    howpublished = {Cryptology ePrint Archive, Report 2015/258},
    year = {2015},
    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.