@misc{cryptoeprint:2013:513,
author = {Stephen Chong and Eran Tromer and Jeffrey A. Vaughan},
title = {Enforcing Language Semantics Using Proof-Carrying Data},
howpublished = {Cryptology ePrint Archive, Report 2013/513},
year = {2013},
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.