@misc{cryptoeprint:1996:014,
author = {Oded Goldreich},
title = {The Graph Clustering Problem has a Perfect Zero-Knowledge Proof},
howpublished = {Cryptology ePrint Archive, Report 1996/014},
year = {1996},
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.