@misc{cryptoeprint:2008:053,
author = {Miroslava Sotakova},
title = {Breaking One-Round Key-Agreement Protocols in the Random Oracle Model},
howpublished = {Cryptology ePrint Archive, Report 2008/053},
year = {2008},
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.