Cryptology ePrint Archive: BibTeX Citation of Report 2014/699

@misc{cryptoeprint:2014:699,
    author = {Christina Boura and María Naya-Plasencia and Valentin Suder},
    title = {Scrutinizing and Improving Impossible Differential Attacks: Applications to CLEFIA, Camellia, LBlock and Simon (Full Version)},
    howpublished = {Cryptology ePrint Archive, Report 2014/699},
    year = {2014},
    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.