Cryptology ePrint Archive: BibTeX Citation of Report 2010/139

@misc{cryptoeprint:2010:139,
    author = {Masao Kasahara},
    title = {A New Class of Public Key Cryptosystems Constructed Based on Perfect Error-Correcting Codes Realizing Coding Rate of Exactly 1.0},
    howpublished = {Cryptology ePrint Archive, Report 2010/139},
    year = {2010},
    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.