@misc{cryptoeprint:2006:329,
author = {Shi-hua Zou and Ji-wen Zeng and Jun-jie Quan},
title = {Designated Verifier Signature Scheme Based on Braid Groups},
howpublished = {Cryptology ePrint Archive, Report 2006/329},
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.