@misc{cryptoeprint:2010:617,
author = {Steven D. Galbraith and John M. Pollard and Raminder S. Ruprai},
title = {Computing Discrete Logarithms in an Interval},
howpublished = {Cryptology ePrint Archive, Report 2010/617},
year = {2010},
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.