Cryptology ePrint Archive: BibTeX Citation of Report 2003/169

@misc{cryptoeprint:2003:169,
    author = {Boris Pogorelov and Marina Pudovkina },
    title = {Properties of the Transformation Semigroup of the Solitaire Stream Cipher  },
    howpublished = {Cryptology ePrint Archive, Report 2003/169},
    year = {2003},
    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.