@misc{cryptoeprint:2006:102,
author = {Tatsuaki Okamoto},
title = {Efficient Blind and Partially Blind Signatures Without Random Oracles},
howpublished = {Cryptology ePrint Archive, Report 2006/102},
year = {2006},
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.