@misc{cryptoeprint:2005:024,
author = {A. A. Kalele and V. R. Sule},
title = {Weak keys of the Diffe Hellman key exchange I},
howpublished = {Cryptology ePrint Archive, Report 2005/024},
year = {2005},
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.