@misc{cryptoeprint:2004:106,
author = {P. Tuyls and J. Goseling},
title = {Capacity and Examples of Template Protecting Biometric Authentication Systems},
howpublished = {Cryptology ePrint Archive, Report 2004/106},
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.