@misc{cryptoeprint:2009:544,
author = {Patrick Sol\'e and Natalia Tokareva},
title = {Connections between Quaternary and Binary Bent Functions},
howpublished = {Cryptology ePrint Archive, Report 2009/544},
year = {2009},
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.