@misc{cryptoeprint:2004:037,
author = {Fuw-Yi Yang and Jinn-Ke Jan},
title = {A Provably Secure Scheme for Restrictive Partially Blind Signatures},
howpublished = {Cryptology ePrint Archive, Report 2004/037},
year = {2004},
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.