Cryptology ePrint Archive: BibTeX Citation of Report 2002/012

@misc{cryptoeprint:2002:012,
    author = {F. Hess},
    title = {Exponent Group Signature Schemes and Efficient Identity Based Signature Schemes Based on Pairings},
    howpublished = {Cryptology ePrint Archive, Report 2002/012},
    year = {2002},
    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.