@misc{cryptoeprint:2010:378,
author = {Jin Wang },
title = {Ring Signature and Identity-Based Ring Signature from Lattice Basis Delegation},
howpublished = {Cryptology ePrint Archive, Report 2010/378},
year = {2010},
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.