@misc{cryptoeprint:2004:121,
author = {Tsz Hon Yuen and Victor K. Wei},
title = {Fast and Proven Secure Blind Identity-Based Signcryption from Pairings},
howpublished = {Cryptology ePrint Archive, Report 2004/121},
year = {2004},
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.