\begin{thebibliography}{1}

\bibitem{rfc3324}
M.~Watson, \htmladdnormallink{``Short term requirements for network asserted
  identity,''}{http://www.rfc-editor.org/rfc/rfc3324.txt} RFC 3324, Internet
  Engineering Task Force, Nov. 2002.

\bibitem{draft-mahy-sipping-smime-vs-digest}
R.~Mahy, \htmladdnormallink{``Discussion of suitability: S/{MIME} instead of
  digest authentication in the session initiation protocol
  ({SIP}),''}{http://www.ietf.org/internet-drafts/draft-mahy-sipping-smime-vs-%
digest-00.txt} {Internet Draft}, Internet Engineering Task Force, Oct. 2002.
\newblock Work in progress.

\bibitem{rfc3323}
J.~Peterson, \htmladdnormallink{``A privacy mechanism for the session
  initiation protocol {(SIP)},''}{http://www.rfc-editor.org/rfc/rfc3323.txt}
  RFC 3323, Internet Engineering Task Force, Nov. 2002.

\bibitem{rfc3325}
C.~Jennings, J.~Peterson, and M.~Watson, \htmladdnormallink{``Private
  extensions to the session initiation protocol {(SIP)} for asserted identity
  within trusted networks,''}{http://www.rfc-editor.org/rfc/rfc3325.txt} RFC
  3325, Internet Engineering Task Force, Nov. 2002.

\end{thebibliography}
