@misc{cryptoeprint:2015:008,
author = {Satrajit Ghosh and Aniket Kate},
title = {Post-Quantum Forward-Secure Onion Routing (Future Anonymity in Today’s Budget)},
howpublished = {Cryptology ePrint Archive, Report 2015/008},
year = {2015},
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.