Cryptology ePrint Archive: BibTeX Citation of Report 2013/391

@misc{cryptoeprint:2013:391,
    author = {Itai Dinur and Orr Dunkelman and Nathan Keller and Adi Shamir},
    title = {Key Recovery Attacks on 3-round Even-Mansour, 8-step LED-128, and Full $\mbox{AES}^{2}$},
    howpublished = {Cryptology ePrint Archive, Report 2013/391},
    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.