Cryptology ePrint Archive: BibTeX Citation of Report 2011/499

@misc{cryptoeprint:2011:499,
    author = {Guido Bertoni and Joan Daemen and Michaël Peeters and Gilles Van Assche},
    title = {Duplexing the sponge: single-pass authenticated encryption and other applications},
    howpublished = {Cryptology ePrint Archive, Report 2011/499},
    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.