% File              : spliceas2.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
{Hwang and Chen modified SPLICE/AS}%
% authors
{Tzonelih Hwang and Yung-Hsiang Chen}%
% date of the first publication
{1995}%
% editor name
{}%
% date of submission
{}%
% date of last change, empty or = date of submission
{11/11/2002}

\begin{abstract}
This modified version correct two flaws in \crossref{spliceas}.
Mutual authentication protocol with 
public key cryptography 
with a certification authority
signing and distributing public keys.
\end{abstract}

\begin{core}
\begin{declarations}
\dcl{S, C, AS}{principal}
\dcl{N1, N2, N3}{nonce}
\dcl{T}{timestamp}
\dcl{L}{lifetime}
\dcl{pk, sk}{principal -> key (keypair)}
\end{declarations}

\begin{messages}
\msg{1}{C}{AS}{C, S, N1}
\msg{2}{AS}{C}{AS, \crypt{AS, C, N1, S, pk(S)}{sk(AS)}}
\msg{3}{C}{S}{C, S, \crypt{C, T, L, \crypt{N2}{pk(S)}}{sk(C)}}
\msg{4}{S}{AS}{S, C, N3}
\msg{5}{AS}{S}{AS, \crypt{AS, S, N3, C, pk(C)}{sk(AS)}}
\msg{6}{S}{C}{S, C, \crypt{S, inc(N2)}{pk(C)}}
\end{messages}
\end{core}

\begin{explanation}
See \crossref{spliceas}.
Note that the name of the owner of the public key is
included in certificate to overcomes the flaws of \crossref{spliceas}
presented in \cite{HwangChen_SPLICEAS}
(i.e. a certificate for the public key \code{pk(S)}
is here \code{\crypt{AS, C, N1, S, pk(S)}{sk(AS)}} rather
than \code{\crypt{AS, C, N1, pk(S)}{sk(AS)}} in \crossref{spliceas}).
\end{explanation}

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

\begin{references}
\cite{HwangChen_SPLICEAS}.
\end{references}

\begin{attacks}
\cite{ClarkJacob95}. Only the messages \code{3} and \code{6} are
relevant in this attack, in which the intruder \code{I} learn 
the secret \code{N2}.
This attack concerns both the secrecy of \code{N2} and
its authenticity.
\begin{messages}
\msg{1}{C}{AS}{C, S, N1}
\msg{2}{AS}{C}{AS, \crypt{AS, C, N1, S, pk(S)}{sk(AS)}}
\msg{3}{C}{I(S)}{C, S, \crypt{C, T, L, \crypt{N2}{pk(S)}}{sk(C)}}
\msg{3}{I}{S}{I, S, \crypt{I, T, L, \crypt{N2}{pk(S)}}{sk(I)}}
\msg{4}{S}{AS}{S, I, N3}
\msg{5}{AS}{S}{AS, \crypt{AS, S, N3, I, pk(I)}{sk(AS)}}
\msg{6}{S}{I}{S, I, \crypt{S, inc(N2)}{pk(I)}}
\msg{1}{I}{AS}{I, C, N1'}
\msg{2}{AS}{I}{AS, \crypt{AS, I, N1', C, pk(C)}{sk(AS)}}
\msg{6}{I(S)}{C}{S, C, \crypt{S, inc(N2)}{pk(C)}}
\end{messages}
\end{attacks}

\begin{see} %\crossref{}, see all.aux for labels names
\crossref{spliceas},
\crossref{spliceas3}.
\end{see}

\end{protocol}
\end{document}

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