@misc{cryptoeprint:2010:369,
author = {Debrup Chakraborty and Cuauhtemoc Mancillas-Lopez},
title = {Double Ciphertext Mode : A Proposal for Secure Backup},
howpublished = {Cryptology ePrint Archive, Report 2010/369},
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.