Cryptology ePrint Archive: BibTeX Citation of Report 2011/073

@misc{cryptoeprint:2011:073,
    author = {Simon R. Blackburn, Carlos Cid and Ciaran Mullan},
    title = {Cryptanalysis of three matrix-based key establishment protocols},
    howpublished = {Cryptology ePrint Archive, Report 2011/073},
    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.