@misc{cryptoeprint:2010:560,
author = {J. Loftus and A. May and N.P. Smart and F. Vercauteren},
title = {On CCA-Secure Fully Homomorphic Encryption},
howpublished = {Cryptology ePrint Archive, Report 2010/560},
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.