@misc{cryptoeprint:2005:410,
author = {Victor K. Wei},
title = {Short (resp. Fast) CCA2-Fully-Anonymous Group Signatures using IND-CPA-Encrypted Escrows},
howpublished = {Cryptology ePrint Archive, Report 2005/410},
year = {2005},
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.