Cryptology ePrint Archive: BibTeX Citation of Report 2011/697

@misc{cryptoeprint:2011:697,
    author = {Andrey Bogdanov, Miroslav Knezevic, Gregor Leander, Deniz Toz, Kerem Varici, Ingrid Verbauwhede},
    title = {SPONGENT: The Design Space of Lightweight Cryptographic Hashing},
    howpublished = {Cryptology ePrint Archive, Report 2011/697},
    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.