@misc{cryptoeprint:2006:010,
author = {Steve Babbage and Matthew Dodd},
title = {Finding Characteristic Polynomials with Jump Indices},
howpublished = {Cryptology ePrint Archive, Report 2006/010},
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.