@misc{cryptoeprint:2009:027,
author = {Markus Rückert and Dominique Schröder},
title = {Security of Verifiably Encrypted Signatures},
howpublished = {Cryptology ePrint Archive, Report 2009/027},
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.