39 

    40 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

    41 \begin{frame}[c]

    42 \frametitle{Problems with Key Fobs}

    43 

    44 \begin{columns}

    45 \begin{column}[T]{4cm}

    46 \includegraphics[scale=0.4]{../pics/car-standard.jpg}

    47 \end{column}

    48 

    49 \begin{column}[T]{6cm}\small 

    50 Circumventing the ignition protection:

    51 

    52 \begin{itemize}

    53 \item either dismantling Megamos crypto,

    54 \item or use the diagnostic port to program 

    55   blank keys 

    56 \end{itemize}

    57 

    58 \hspace{14mm}

    59 \includegraphics[scale=0.16]{../pics/Dismantling_Megamos_Crypto.png}

    60 \end{column}

    61 \end{columns}

    62 

    63 

    64 

    65 \end{frame}

    66 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   

    67 

    68 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

    69 \begin{frame}[c]

    70 \frametitle{Protocols}

    71 

    72 \begin{center}

    73 \includegraphics[scale=0.11]{../pics/keyfob.jpg}

    74 \quad

    75 \includegraphics[scale=0.232]{../pics/starbucks.jpg}

    76 \end{center}

    77 

    78 \begin{itemize}

    79 \item The point is that we have no control over the network

    80 

    81 \item We want to avoid that a message exchange (a protocol) can

    82 be attacked without detection

    83 \end{itemize}

    84   

    85 \end{frame}

    86 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   

    87 

    88 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

    89 \begin{frame}[c]

    90 \frametitle{G20 Summit in 2009}

    91 

    92 \begin{center}

    93 \includegraphics[scale=0.1]{../pics/snowden.jpg}

    94 \end{center}

    95 

    96 \small

    97 \begin{itemize}

    98 \item Snowden documents reveal ``that during G20

    99       meetings\dots{}GCHQ used 

   100       `ground-breaking intelligence capabilities' to intercept

   101       the communications of visiting delegations. This

   102       included setting up internet cafes where they used an

   103       email interception program and key-logging software to

   104       spy on delegates' use of computers\ldots''

   105 

   106 \item ``The G20 spying appears to have been organised for the

   107       more mundane purpose of securing an advantage in

   108       meetings.'' 

   109 \end{itemize}

   110   

   111 \end{frame}

   112 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   

   113 

   114 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

   115 \begin{frame}[c]

   116 \frametitle{Interlock Protocol}

   117 

   118 The interlock protocol (``best bet'' against MITM):

   119 

   120 \begin{center}

   121 \begin{tabular}{ll@{\hspace{2mm}}l}

   122 1. & \bl{$A \to B :$} & \bl{$K^{pub}_A$}\\

   123 2. & \bl{$B \to A :$} & \bl{$K^{pub}_B$}\\

   124 3. & & \bl{$\{A,m\}_{K^{pub}_B} \;\mapsto\; H_1,H_2$}\\

   125    & & \bl{$\{B,m'\}_{K^{pub}_A} \;\mapsto\; M_1,M_2$}\\

   126 4. & \bl{$A \to B :$} & \bl{$H_1$}\\

   127 5. & \bl{$B \to A :$} & \bl{$\{H_1, M_1\}_{K^{pub}_A}$}\\

   128 6. & \bl{$A \to B :$} & \bl{$\{H_2, M_1\}_{K^{pub}_B}$}\\

   129 7. & \bl{$B \to A :$} & \bl{$M_2$}

   130 \end{tabular}

   131 \end{center}

   132 

   133 \end{frame}

   134 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%  

   135 

   136 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

   137 \begin{frame}[c]

   138 

   139 \begin{center}

   140 \begin{tabular}{l@{\hspace{9mm}}l}

   141 \begin{tabular}[t]{@{}l@{}}

   142 \bl{$A \to C : K^{pub}_A$}\\

   143 \bl{$C \to B : K^{pub}_C$}\\

   144 \bl{$B \to C : K^{pub}_B$}\\

   145 \bl{$C \to A : K^{pub}_C$}\medskip\\

   146 \bl{$\{A,m\}_{K^{pub}_C} \;\mapsto\; H_1,H_2$}\\

   147 \bl{$\{B,n\}_{K^{pub}_C} \;\mapsto\; M_1,M_2$}\bigskip\\

   148 \bl{$\{C,a\}_{K^{pub}_B} \;\mapsto\; C_1,C_2$}\\

   149 \bl{$\{C,b\}_{K^{pub}_A} \;\mapsto\; D_1,D_2$}

   150 \end{tabular} &

   151 \begin{tabular}[t]{@{}l@{}}

   152 \bl{$A \to C : H_1$}\\

   153 \bl{$C \to B : C_1$}\\

   154 \bl{$B \to C : \{C_1, M_1\}_{K^{pub}_C}$}\\

   155 \bl{$C \to A : \{H_1, D_1\}_{K^{pub}_A}$}\\

   156 \bl{$A \to C : \{H_2, D_1\}_{K^{pub}_C}$}\\

   157 \bl{$C \to B : \{C_2, M_1\}_{K^{pub}_B}$}\\

   158 \bl{$B \to C : M_2$}\\

   159 \bl{$C \to A : D_2$}

   160 \end{tabular}

   161 \end{tabular}

   162 \end{center}

   163 

   164 \end{frame}

   165 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%  

   166 

   167 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

   168 \begin{frame}[c]

   169 

   170 \begin{itemize}

   171 \item you have to ask something that cannot imitated 

   172   (requires \bl{$A$} and \bl{$B$} know each other)

   173 \item what happens if \bl{$m$} and \bl{$n$} are voice

   174   messages?\bigskip  

   175 

   176 \item the moral: establishing a secure connection from ``zero'' is

   177 almost impossible---you need to rely on some established 

   178 trust\medskip

   179 

   180 \item that is why we rely on certificates, which however are

   181 badly, badly realised (just today a POODLE attack against SSL)

   182 

   183 \end{itemize}

   184 

   185 \end{frame}

   186 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%  

   187