@misc{cryptoeprint:2011:223,
author = {Zeng Bing and Chen Liang and Tang Xueming},
title = {A Perfectly Binding Commitment Scheme Against Quantum Attacks},
howpublished = {Cryptology ePrint Archive, Report 2011/223},
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.