@misc{cryptoeprint:2007:282,
author = {Johannes Bl\"omer \and Volker Krummel},
title = {Analysis of countermeasures against access driven cache attacks on AES},
howpublished = {Cryptology ePrint Archive, Report 2007/282},
year = {2007},
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.