diff -r 2522dea979d0 -r bc48791bb3a9 slides07.tex --- a/slides07.tex Tue Nov 13 09:29:30 2012 +0000 +++ b/slides07.tex Tue Nov 13 10:46:08 2012 +0000 @@ -642,7 +642,25 @@ %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% - +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +\mode{ +\begin{frame}[c] +\frametitle{One More Thing} + +\begin{itemize} +\item I arrived at King's last year +\item Maxime Crochemore told me about a string algorithm (suffix sorting) that appeared at a +conference in 2007 (ICALP) +\item ``horribly incomprehensible'', no implementation, but claims to be the best \bl{$O(n + k)$} algorithm\bigskip\pause + +\item Jian Jiang found 1 error and 1 superfluous step +\item he received 88\% for the project and won the prize for the best 7CCSMPRJ project +\item no proof \ldots{} yet +\end{itemize} + +\end{frame}} +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \mode{ @@ -777,7 +795,7 @@ \item an engine \bl{$E$} and a transponder \bl{$T$} share a key \bl{$K$}\bigskip \item \bl{$E$} sends out a \alert{nonce} \bl{$N$} (random number) to \bl{$T$}\bigskip \item \bl{$T$} responds with \bl{$\{N\}_K$}\bigskip - \item if \bl{$E$} receives \bl{$\{N\}_K$} from \bl{$T$} then starts engine + \item if \bl{$E$} receives \bl{$\{N\}_K$} from \bl{$T$}, it starts engine \end{itemize} \end{frame}} @@ -786,7 +804,7 @@ %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \mode{ \begin{frame}[c] - \frametitle{Challenge-Response Protokol} + \frametitle{Challenge-Response Protocol} \begin{center} \bl{\begin{tabular}{l} @@ -805,6 +823,41 @@ \end{frame}} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + \mode{ + \begin{frame}[c] + \frametitle{Exchange of a Fresh Key} + + \begin{itemize} + \item assumption \bl{$K_{AB}$} is only known to \bl{$A$} and \bl{$B$}\bigskip + \item \bl{$A \,\text{sends}\, B : A, \{N_A\}_{K_{AB}}$} + \item \bl{$B\,\text{sends}\, A : \{N_A + 1, N_B\}_{K_{AB}}$} + \item \bl{$A \,\text{sends}\, B : \{N_B + 1\}_{K_{AB}}$} + \item \bl{$B \,\text{sends}\, A : \{K^{new}_{AB}, N^{new}_B\}_{K_{AB}}$} + \end{itemize}\bigskip\pause + + We hope \bl{$K^{new}_{AB}$} is only known to \bl{$A$} and \bl{$B$}.\\ + \bl{$N^{new}_B$} is to be used in future messages + \end{frame}} + %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + + %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + \mode{ + \begin{frame}[c] + \frametitle{The Attack} + +An intruder \bl{$I$} convinces \bl{$B$} to accept an old compromised key + +\begin{itemize} + \item \bl{$A \,\text{sends}\, B : A, \{N_A\}_{K_{AB}}$} + \item \bl{$B\,\text{sends}\, A : \{N_A + 1, N_B\}_{K_{AB}}$} + \item \bl{$A \,\text{sends}\, B : \{N_B + 1\}_{K_{AB}}$} + \item \bl{$B \,\text{sends}\, A : \{K^{new}_{AB}, N^{new}_B\}_{K_{AB}}$}\pause + \end{itemize} + + \end{frame}} + %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + \end{document} %%% Local Variables: