@misc{cryptoeprint:2004:349,
author = {Dong Jin PARK and Pil Joong LEE},
title = {A DPA Attack on the Improved Ha-Moon Algorithm},
howpublished = {Cryptology ePrint Archive, Report 2004/349},
year = {2004},
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.