@misc{cryptoeprint:2014:491,
author = {Michael Clear and Ciar\'{a}n McGoldrick},
title = {Bootstrappable Identity-Based Fully Homomorphic Encryption},
howpublished = {Cryptology ePrint Archive, Report 2014/491},
year = {2014},
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.