@misc{cryptoeprint:2011:087,
author = {Yevgeniy Dodis and Iftach Haitner and Aris Tentes},
title = {On the Instantiability of Hash-and-Sign RSA Signatures},
howpublished = {Cryptology ePrint Archive, Report 2011/087},
year = {2011},
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.