% File              : wideMouthedFrogLowe.tex
% Version           : $Revision: 1.1 $
% Last-modified     : $Date: 2005/01/04 11:45:32 $
% Last-modifier     : FJ

\documentclass{splib}

\begin{document}
% main environment
\begin{protocol}%
% name
{Lowe modified Wide Mouthed Frog}%
% authors
{Gavin Lowe}%
% date of the first publication
{1997}%
% editor name
{}%
% date of submission
{}%
% date of last change, empty or = date of submission
{20/11/2002}

\begin{abstract}
An modified version of \crossref{wideMouthedFrog}.
Exchanged of a fresh shared key.
Symmetric key cryptography with server and timestamps.
\end{abstract}

\begin{core}
\begin{declarations}
\dcl{A, S}{principal}
\dcl{Kas, Kbs, Kab}{symkey}
\dcl{Nb}{nonce}
\dcl{Ta, Ts}{timestamp}
\dcl{suc}{nonce -> nonce}
\end{declarations}

\begin{messages}
\msg{1}{A}{S}{A, \crypt{Ta, B, Kab}{Kas}}
\msg{2}{S}{B}{\crypt{Ts, A, Kab}{Kbs}}
\msg{3}{B}{A}{\crypt{Nb}{Kab}}
\msg{4}{A}{B}{\crypt{succ(Nb)}{Kab}}
\end{messages}
\end{core}

\begin{explanation}
Two messages have been appened to \crossref{wideMouthedFrog}
for mutual authentification of \code{A} and \code{B}
(\emph{nonce handshake}).
\end{explanation}

\begin{remark}
The two final messages were added by Lowe to the \crossref{wideMouthedFrog}
protocol to prevent an attack claimed in \cite{Lowe97}
which actually fails against the complete original specification 
of the protocol in \cite{BurrowsAbadiNeedham89}, see \crossref{wideMouthedFrog}.
\end{remark}


\begin{property}
See \crossref{wideMouthedFrog}.
\end{property}

\begin{references}
\cite{Lowe97}
\end{references}

\begin{see}
\crossref{wideMouthedFrog}
\end{see}

\end{protocol}
\end{document}

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