Cryptology ePrint Archive: BibTeX Citation of Report 2013/404

@misc{cryptoeprint:2013:404,
    author = {Ray Beaulieu and Douglas Shors and Jason Smith and Stefan Treatman-Clark and Bryan Weeks and Louis Wingers},
    title = {The SIMON and SPECK Families of Lightweight Block Ciphers},
    howpublished = {Cryptology ePrint Archive, Report 2013/404},
    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.