Cryptology ePrint Archive: BibTeX Citation of Report 2007/156

@misc{cryptoeprint:2007:156,
    author = {Gergei Bana and Koji Hasebe and Mitsuhiro Okada},
    title = {Computational Semantics for Basic Protocol Logic - A Stochastic Approach},
    howpublished = {Cryptology ePrint Archive, Report 2007/156},
    year = {2007},
    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.