@misc{cryptoeprint:2006:392,
author = {Katherine E. Stange},
title = {The Tate Pairing via Elliptic Nets},
howpublished = {Cryptology ePrint Archive, Report 2006/392},
year = {2006},
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.