@misc{cryptoeprint:2008:324,
author = {Varad Kirtane and C.Pandu Rangan},
title = {RSA-TBOS Signcryption with Proxy Re-encryption.},
howpublished = {Cryptology ePrint Archive, Report 2008/324},
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.