@misc{cryptoeprint:2010:503,
author = {Seung Geol Choi and Aggelos Kiayias and Tal Malkin},
title = {BiTR: Built-in Tamper Resilience},
howpublished = {Cryptology ePrint Archive, Report 2010/503},
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.