@misc{cryptoeprint:2011:251,
author = {Sanjam Garg and Vipul Goyal and Abhishek Jain and Amit Sahai},
title = {Concurrently Secure Computation in Constant Rounds},
howpublished = {Cryptology ePrint Archive, Report 2011/251},
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.