@misc{cryptoeprint:2007:165,
author = {Arnab Roy and Anupam Datta and Ante Derek and John C. Mitchell},
title = {Inductive Proof Method for Computational Secrecy},
howpublished = {Cryptology ePrint Archive, Report 2007/165},
year = {2007},
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.