@misc{cryptoeprint:2003:176,
author = {S. Gangopadhyay and P. H. Keskar and S. Maitra},
title = {Patterson-Wiedemann Construction Revisited},
howpublished = {Cryptology ePrint Archive, Report 2003/176},
year = {2003},
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.