
diff -r 98ae49ffc262 -r 62985f147c85 slides/bak-slides07.tex
--- a/slides/bak-slides07.tex	Tue Sep 26 12:03:24 2017 +0100
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,739 +0,0 @@
-\documentclass[dvipsnames,14pt,t]{beamer}
-\usepackage{proof}
-\usepackage{beamerthemeplaincu}
-%\usepackage[T1]{fontenc}
-%\usepackage[latin1]{inputenc}
-\usepackage{mathpartir}
-\usepackage{isabelle}
-\usepackage{isabellesym}
-\usepackage[absolute,overlay]{textpos}
-\usepackage{ifthen}
-\usepackage{tikz}
-\usepackage{courier}
-\usepackage{listings}
-\usetikzlibrary{arrows}
-\usetikzlibrary{positioning}
-\usetikzlibrary{calc}
-\usepackage{graphicx} 
-\usetikzlibrary{shapes}
-\usetikzlibrary{shadows}
-\usetikzlibrary{plotmarks}
-
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-\renewcommand{\isamarkupcmt}[1]{#1}
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-
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-% Isabelle characters
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-\definecolor{javadocblue}{rgb}{0.25,0.35,0.75} % javadoc
-
-\lstset{language=Java,
-	basicstyle=\ttfamily,
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-
-\lstdefinelanguage{scala}{
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-\lstset{language=Scala,
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-	numbersep=10pt,
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-
-% beamer stuff 
-\renewcommand{\slidecaption}{APP 07, King's College London, 19 November 2013}
-\newcommand{\dn}{\stackrel{\mbox{\scriptsize def}}{=}}% for definitions
-\newcommand{\bl}[1]{\textcolor{blue}{#1}}
-
-
-
-\begin{document}
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}<1>[t]
-\frametitle{%
-  \begin{tabular}{@ {}c@ {}}
-  \\
-  \LARGE Access Control and \\[-3mm] 
-  \LARGE Privacy Policies (7)\\[-6mm] 
-  \end{tabular}}\bigskip\bigskip\bigskip
-
-  %\begin{center}
-  %\includegraphics[scale=1.3]{pics/barrier.jpg}
-  %\end{center}
-
-\normalsize
-  \begin{center}
-  \begin{tabular}{ll}
-  Email:  & christian.urban at kcl.ac.uk\\
-  Office: & S1.27 (1st floor Strand Building)\\
-  Slides: & KEATS (also homework is there)\\
-  \end{tabular}
-  \end{center}
-
-
-\end{frame}}
- %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%     
- 
- %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  \mode<presentation>{
-  \begin{frame}[c]
-  \frametitle{}
-
-  Recall the following scenario:
-
-  \begin{itemize}
-  \item If \textcolor{blue}{Admin} says that \textcolor{blue}{\isa{file}} 
-  should be deleted, then this file must be deleted.
-  \item \textcolor{blue}{Admin} trusts \textcolor{blue}{Bob} to decide whether 
-  \textcolor{blue}{\isa{file}} should be deleted (delegation).
-  \item \textcolor{blue}{Bob} wants to delete \textcolor{blue}{\isa{file}}.
-  \end{itemize}\bigskip
-
-  \small
-  \textcolor{blue}{\isa{{\isaliteral{5C3C47616D6D613E}{\isasymGamma}}\ {\isaliteral{3D}{\isacharequal}}}\small\begin{tabular}{l}
-  \isa{{\isaliteral{28}{\isacharparenleft}}Admin\ says\ del{\isaliteral{5F}{\isacharunderscore}}file\isaliteral{5C3C5E697375623E}{}{\isaliteral{29}{\isacharparenright}}\ {\isaliteral{5C3C52696768746172726F773E}{\isasymRightarrow}}\ del{\isaliteral{5F}{\isacharunderscore}}file\isaliteral{5C3C5E697375623E}{}},\\
-  \isa{{\isaliteral{28}{\isacharparenleft}}Admin\ says\ {\isaliteral{28}{\isacharparenleft}}{\isaliteral{28}{\isacharparenleft}}Bob\ says\ del{\isaliteral{5F}{\isacharunderscore}}file\isaliteral{5C3C5E697375623E}{}{\isaliteral{29}{\isacharparenright}}\ {\isaliteral{5C3C52696768746172726F773E}{\isasymRightarrow}}\ del{\isaliteral{5F}{\isacharunderscore}}file\isaliteral{5C3C5E697375623E}{}{\isaliteral{29}{\isacharparenright}}{\isaliteral{29}{\isacharparenright}}},\\
-  \isa{Bob\ says\ del{\isaliteral{5F}{\isacharunderscore}}file\isaliteral{5C3C5E697375623E}{}}\\
-  \end{tabular}}\medskip
-
-  \textcolor{blue}{\isa{{\isaliteral{5C3C47616D6D613E}{\isasymGamma}}\ {\isaliteral{5C3C7475726E7374696C653E}{\isasymturnstile}}\ del{\isaliteral{5F}{\isacharunderscore}}file\isaliteral{5C3C5E697375623E}{}}}
-  \end{frame}}
-  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}[c]
-\frametitle{\begin{tabular}{@ {\hspace{-2mm}}c@ {}}The Access Control Problem\end{tabular}}
-
-
-\begin{center}
-  \begin{tikzpicture}[scale=1]
-  
-  \draw[line width=1mm] (-.3, -0.5) rectangle (1.5,2);
-  \draw (-2.7,1) node {\begin{tabular}{l}access\\request\\ (\bl{$F$})\end{tabular}};
-  \draw (4.2,1) node {\begin{tabular}{l}provable/\\not provable\end{tabular}};
-  \draw (0.6,0.8) node {\footnotesize \begin{tabular}{l}AC-\\ Checker:\\ applies\\ inference\\ rules\end{tabular}};
- 
-  \draw[red, ->, line width = 2mm] (1.7,1) -- (2.7,1); 
-  \draw[red,<-, line width = 2mm] (-0.6,1) -- (-1.6,1);
-  \draw[red, <-, line width = 3mm] (0.6,2.2) -- (0.6,3.2); 
-  
-  \draw (0.6,4) node {\begin{tabular}{l}\large Access Policy (\boldmath\bl{$\Gamma$})\end{tabular}};
-
-  \end{tikzpicture}
-\end{center}
-
-\end{frame}}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}[c]
-
-\begin{itemize}
-\item \bl{$P \,\text{says}\, F$} means \bl{$P$} can send a ``signal'' \bl{$F$} through a wire, or
-can make a ``statement'' \bl{$F$}\bigskip\pause
-
-\item \bl{$P$} is entitled to do \bl{$F$}\smallskip\\ 
-\bl{$P \,\text{controls}\, F \,\dn\, (P\,\text{says}\, F) \Rightarrow F$}\medskip
-
-\begin{center}
-\bl{\infer{\Gamma \vdash F}{\Gamma \vdash P\,\text{controls}\, F & \Gamma \vdash P\,\text{says}\,F}}
-\end{center}
-
-
-\end{itemize}
-
-\end{frame}}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  \mode<presentation>{
-  \begin{frame}[c]
-  \frametitle{Security Levels}
-  \small
-
-  \begin{itemize}
-  \item Top secret (\bl{$T\!S$})
-  \item Secret (\bl{$S$})
-  \item Public (\bl{$P$})
-  \end{itemize}
-
-  \begin{center}
-  \bl{$slev(P) < slev(S) < slev(T\!S)$}\pause
-  \end{center}
-
-  \begin{itemize}
-  \item Bob has a clearance for ``secret''
-  \item Bob can read documents that are public or sectret, but not top secret
-  \end{itemize}
-
-  \end{frame}}
-  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-%
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  \mode<presentation>{
-  \begin{frame}[c]
-  \frametitle{Reading a File}
-
-  \bl{\begin{center}
-  \begin{tabular}{c}
-  \begin{tabular}{@ {}l@ {}}
-  \only<2->{\textcolor{red}{$slev($File$)$ $<$ $slev($Bob$)$ $\Rightarrow$}}\\ 
-  \only<2->{\hspace{3cm}}Bob controls Permitted $($File, read$)$\\
-  Bob says Permitted $($File, read$)$\only<2->{\\}
-  \only<2>{\textcolor{red}{$slev($File$)$ $<$ $slev($Bob$)$}}%
-  \only<3>{\textcolor{red}{$slev($File$)$ $=$ $P$}\\}%
-  \only<3>{\textcolor{red}{$slev($Bob$)$ $=$ $S$}\\}%
-  \only<3>{\textcolor{red}{$slev(P)$ $<$ $slev(S)$}\\}%
-  \end{tabular}\\
-  \hline
-  Permitted $($File, read$)$
-  \end{tabular}
-  \end{center}}
-
-  \end{frame}}
-  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-%
-
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  \mode<presentation>{
-  \begin{frame}[c]
-  \frametitle{Substitution Rule}
-  \small
-  
-  \bl{\begin{center}
-  \begin{tabular}{c}
-  $\Gamma \vdash slev(P) = l_1$ \hspace{4mm} $\Gamma \vdash slev(Q) = l_2$
-  \hspace{4mm} $\Gamma \vdash l_1 < l_2$\\\hline
-  $\Gamma \vdash slev(P) < slev(Q)$
-  \end{tabular}
-  \end{center}}\bigskip\pause
-
-  \begin{itemize}
-  \item \bl{$slev($Bob$)$ $=$ $S$}
-  \item \bl{$slev($File$)$ $=$ $P$}
-  \item \bl{$slev(P) < slev(S)$}
-  \end{itemize}
-
-  \end{frame}}
-  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-%
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  \mode<presentation>{
-  \begin{frame}[c]
-  \frametitle{Reading a File}
-
-  \bl{\begin{center}
-  \begin{tabular}{c}
-  \begin{tabular}{@ {}l@ {}}
-  $slev($File$)$ $<$ $slev($Bob$)$ $\Rightarrow$\\ 
-  \hspace{3cm}Bob controls Permitted $($File, read$)$\\
-  Bob says Permitted $($File, read$)$\\
-  $slev($File$)$ $=$ $P$\\
-  $slev($Bob$)$ $=$ $T\!S$\\
-  \only<1>{\textcolor{red}{$?$}}%
-  \only<2>{\textcolor{red}{$slev(P) < slev(S)$}\\}%
-  \only<2>{\textcolor{red}{$slev(S) < slev(T\!S)$}}%
-  \end{tabular}\\
-  \hline
-  Permitted $($File, read$)$
-  \end{tabular}
-  \end{center}}
-
-  \end{frame}}
-  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-%
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  \mode<presentation>{
-  \begin{frame}[c]
-  \frametitle{Transitivity Rule}
-  \small
-  
-  \bl{\begin{center}
-  \begin{tabular}{c}
-  $\Gamma \vdash l_1 < l_2$ 
-  \hspace{4mm} $\Gamma \vdash l_2 < l_3$\\\hline
-  $\Gamma \vdash l_1 < l_3$
-  \end{tabular}
-  \end{center}}\bigskip
-
-  \begin{itemize}
-  \item \bl{$slev(P) < slev (S)$}
-  \item \bl{$slev(S) < slev (T\!S)$}
-  \item[] \bl{$slev(P) < slev (T\!S)$}
-  \end{itemize}
-
-  \end{frame}}
-  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-%
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  \mode<presentation>{
-  \begin{frame}[c]
-  \frametitle{Reading Files}
-
-  \begin{itemize}
-  \item Access policy for Bob for reading
-  \end{itemize}
-
-  \bl{\begin{center}
-  \begin{tabular}{c}
-  \begin{tabular}{@ {}l@ {}}
-  $\forall f.\;slev(f)$ \only<1>{$<$}\only<2>{\textcolor{red}{$\le$}} $slev($Bob$)$ $\Rightarrow$\\ 
-  \hspace{3cm}Bob controls Permitted $(f$, read$)$\\
-  Bob says Permitted $($File, read$)$\\
-  $slev($File$)$ $=$ \only<1>{$P$}\only<2>{\textcolor{red}{$T\!S$}}\\
-  $slev($Bob$)$ $=$ $T\!S$\\
-  $slev(P) < slev(S)$\\
-  $slev(S) < slev(T\!S)$
-  \end{tabular}\\
-  \hline
-  Permitted $($File, read$)$
-  \end{tabular}
-  \end{center}}
-
-  \end{frame}}
-  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-%
-
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  \mode<presentation>{
-  \begin{frame}[c]
-  \frametitle{Writing Files}
-
-  \begin{itemize}
-  \item Access policy for Bob for {\bf writing}
-  \end{itemize}
-
-  \bl{\begin{center}
-  \begin{tabular}{c}
-  \begin{tabular}{@ {}l@ {}}
-  $\forall f.\;slev($Bob$)$ $\le$ $slev(f)$ $\Rightarrow$\\ 
-  \hspace{3cm}Bob controls Permitted $(f$, write$)$\\
-  Bob says Permitted $($File, write$)$\\
-  $slev($File$)$ $=$ $T\!S$\\
-  $slev($Bob$)$ $=$ $S$\\
-  $slev(P) < slev(S)$\\
-  $slev(S) < slev(T\!S)$
-  \end{tabular}\\
-  \hline
-  Permitted $($File, write$)$
-  \end{tabular}
-  \end{center}}
-
-  \end{frame}}
-  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-%
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  \mode<presentation>{
-  \begin{frame}[c]
-  \frametitle{Encrypted Messages}
-
-  \begin{itemize}
-  \item Alice sends a message \bl{$m$}
-  \begin{center}
-  \bl{Alice says $m$}
-  \end{center}\medskip\pause
-
-  \item Alice sends an encrypted message \bl{$m$}\\ (with key \bl{$K$})
-  \begin{center}
-  \bl{Alice says $\{m\}_K$}
-  \end{center}\medskip\pause
-
-  \item Decryption of Alice's message\smallskip
-  \begin{center}
-  \bl{\mbox{\infer{\Gamma \vdash \text{Alice}\;\text{says}\;m}
-              {\Gamma \vdash \text{Alice}\;\text{says}\;\{m\}_K & \Gamma \vdash \text{Alice}\,\text{says}\,K}}}
-  \end{center}
-  \end{itemize}
-
-  \end{frame}}
-  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
-  
- %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  \mode<presentation>{
-  \begin{frame}[c]
-  \frametitle{Encryption}
-
-  \begin{itemize}
-  \item Encryption of a message\smallskip
-  \begin{center}
-  \bl{\mbox{\infer{\Gamma \vdash \text{Alice}\;\text{says}\;\{m\}_K}
-              {\Gamma \vdash \text{Alice}\;\text{says}\;m & \Gamma \vdash \text{Alice}\,\text{says}\,K}}}
-  \end{center}
-  \end{itemize}
-
-  \end{frame}}
-  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%     
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}[c]
-\frametitle{Trusted Third Party}
-
-Simple protocol for establishing a secure connection via a mutually
-trusted 3rd party (server):
-
-\begin{center}
-\begin{tabular}{@ {\hspace{-7mm}}l@{\hspace{2mm}}r@ {\hspace{1mm}}l}
-Message 1 & \bl{$A \rightarrow S :$} & \bl{$A, B$}\\
-Message 2 & \bl{$S \rightarrow A :$} & \bl{$\{K_{AB}\}_{K_{AS}}$} and \bl{$\{\{K_{AB}\}_{K_{BS}} \}_{K_{AS}}$}\\
-Message 3 & \bl{$A \rightarrow B :$} & \bl{$\{K_{AB}\}_{K_{BS}} $}\\
-Message 4 & \bl{$A \rightarrow B :$} & \bl{$\{m\}_{K_{AB}}$}\\
-\end{tabular}
-\end{center}
-
-\end{frame}}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
-
-   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  \mode<presentation>{
-  \begin{frame}[c]
-  \frametitle{Sending Rule}
-
-  \bl{\begin{center}
-  \mbox{$\infer{\Gamma \vdash Q \;\text{says}\; F}
-              {\Gamma \vdash P \;\text{says}\; F & \Gamma \vdash P \;\text{sends}\; Q : F}$}
-  \end{center}}\bigskip\pause
-  
-  \bl{$P \,\text{sends}\, Q : F \dn$}\\
-  \hspace{6mm}\bl{$(P \,\text{says}\, F) \Rightarrow (Q \,\text{says}\, F)$}
-
-  \end{frame}}
-  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%     
-  
-    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  \mode<presentation>{
-  \begin{frame}[c]
-  \frametitle{Trusted Third Party}
-
-  \begin{center}
-  \bl{\begin{tabular}{l}
-  $A$ sends $S$ : $\text{Connect}(A,B)$\\  
-  \bl{$S \,\text{says}\, (\text{Connect}(A,B) \Rightarrow$}\\ 
-  \hspace{2.5cm}\bl{$\{K_{AB}\}_{K_{AS}} \wedge 
-  \{\{K_{AB}\}_{K_{BS}}\}_{K_{AS}})$}\\
- $S$ sends $A$ : $\{K_{AB}\}_{K_{AS}}$ \bl{$\wedge$} $\{\{K_{AB}\}_{K_{BS}}\}_{K_{AS}}$\\
-  $A$ sends $B$ : $\{K_{AB}\}_{K_{BS}}$\\
-  $A$ sends $B$ : $\{m\}_{K_{AB}}$
-  \end{tabular}}
-  \end{center}\bigskip\pause
-  
-  
-  \bl{$\Gamma \vdash B \,\text{says} \, m$}?
-  \end{frame}}
-  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%      
-
-   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  \mode<presentation>{
-  \begin{frame}[c]
-  \frametitle{Public/Private Keys}
-
-  \begin{itemize}
-  \item Bob has a private and public key: \bl{$K_{Bob}^{pub}$}, \bl{$K_{Bob}^{priv}$}\bigskip
-  \begin{center}
-  \bl{\mbox{\infer{\Gamma \vdash \text{Alice}\;\text{says}\;m}
-              {\Gamma \vdash \text{Alice}\;\text{says}\;\{m\}_{K_{Bob}^{pub}} & 
-               \Gamma \vdash K_{Bob}^{priv}}}}
-  \end{center}\bigskip\pause
-
-  \item this is {\bf not} a derived rule! 
-  \end{itemize}
-
-  \end{frame}}
-  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%      
-  
-
-%  \begin{itemize}
-%  \item Alice calls Sam for a key to communicate with Bob
-%  \item Sam responds with a key that Alice can read and a key Bob can read (pre-shared)
- % \item Alice sends the message encrypted with the key and the second key it recieved
- % \end{itemize}\bigskip
-  
-   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  \mode<presentation>{
-  \begin{frame}[c]
-  \frametitle{Sending Rule}
-
-
-  \bl{\begin{center}
-  \mbox{\infer{\Gamma \vdash Q \;\textit{says}\; F}
-              {\Gamma \vdash P \;\textit{says}\; F & \Gamma \vdash P \;\textit{sends}\; Q : F}}
-  \end{center}}\bigskip\pause
-  
-  \bl{$P \,\text{sends}\, Q : F \dn$}\\
-  \hspace{6mm}\bl{$(P \,\text{says}\, F) \Rightarrow (Q \,\text{says}\, F)$}
-
-  \end{frame}}
-  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%     
-  
-    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  \mode<presentation>{
-  \begin{frame}[c]
-  \frametitle{Trusted Third Party}
-
-  \begin{center}
-  \bl{\begin{tabular}{l}
-  $A$ sends $S$ : $\textit{Connect}(A,B)$\\  
-  \bl{$S \,\text{says}\, (\textit{Connect}(A,B) \Rightarrow$}\\ 
-  \hspace{2.5cm}\bl{$\{K_{AB}\}_{K_{AS}} \wedge 
-  \{\{K_{AB}\}_{K_{BS}}\}_{K_{AS}})$}\\
- $S$ sends $A$ : $\{K_{AB}\}_{K_{AS}}$ \bl{$\wedge$} $\{\{K_{AB}\}_{K_{BS}}\}_{K_{AS}}$\\
-  $A$ sends $B$ : $\{K_{AB}\}_{K_{BS}}$\\
-  $A$ sends $B$ : $\{m\}_{K_{AB}}$
-  \end{tabular}}
-  \end{center}\bigskip\pause
-  
-  
-  \bl{$\Gamma \vdash B \,\text{says} \, m$}?
-  \end{frame}}
-  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
-  
-   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  \mode<presentation>{
-  \begin{frame}[c]
-  \frametitle{Challenge-Response Protocol}
-
- \begin{itemize}
- \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{$T$}, it starts engine
- \end{itemize}	
-  
-  \end{frame}}
-  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  
-    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  \mode<presentation>{
-  \begin{frame}[c]
-  \frametitle{Challenge-Response Protocol}
-
-  \begin{center}
-  \bl{\begin{tabular}{l}
-  $E \;\text{says}\; N$\hfill(start)\\
-  $E \;\text{sends}\; T : N$\hfill(challenge)\\
-  $(T \;\text{says}\; N) \Rightarrow (T \;\text{sends}\; E : \{N\}_K \wedge$\\
-  \hspace{3.5cm} $T \;\text{sends}\; E : \text{Id}(T))$\;\;\;\hfill(response)\\
- $T \;\text{says}\; K$\hfill(key)\\
- $T \;\text{says}\; \text{Id}(T)$\hfill(identity)\\
-  $(E \;\text{says}\; \{N\}_K \wedge E \;\text{says}\; \text{Id}(T)) \Rightarrow$\\
-   \hspace{5cm}$ \text{start\_engine}(T)$\hfill(engine)\\
-  \end{tabular}}
-  \end{center}\bigskip 
-  
-  \bl{$\Gamma \vdash \text{start\_engine}(T)$}?
-  \end{frame}}
-  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
-     
-  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  \mode<presentation>{
-  \begin{frame}[c]
-  \frametitle{Exchange of a Fresh Key}
-
-\bl{$A$} and \bl{$B$} share a (``super-secret'') key \bl{$K_{AB}$} and want to share another key
-
- \begin{itemize}
- \item assumption \bl{$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}}$}
-  \item<2> \bl{$A \,\text{sends}\, B : \{msg\}_{K^{new}_{AB}}$}
- \end{itemize}\bigskip
-  
-  Assume \bl{$K^{new}_{AB}$} is compromised by \bl{$I$}
-  \end{frame}}
-  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%    
-     
- %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  \mode<presentation>{
-  \begin{frame}[c]
-  \frametitle{The Attack}
-
-An intruder \bl{$I$} convinces \bl{$A$} to accept the compromised key \bl{$K^{new}_{AB}$}\medskip 
-
-\begin{minipage}{1.1\textwidth}
-\begin{itemize}
- \item \bl{$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}}$}\;\;recorded by \bl{$I$}\pause
-  \item \bl{$A \,\text{sends}\, B :  A, \{M_A\}_{K_{AB}}$} 
- \item \bl{$B\,\text{sends}\, A : \{M_A + 1, M_B\}_{K_{AB}}$}
- \item \bl{$A \,\text{sends}\, B : \{M_B + 1\}_{K_{AB}}$}
-  \item \bl{$B \,\text{sends}\, I : \{K^{newer}_{AB}, N^{newer}_B\}_{K_{AB}}$}\;intercepted by \bl{$I$}
-  \item \bl{$I \,\text{sends}\, A : \{K^{new}_{AB}, N^{new}_B\}_{K_{AB}}$}\pause
-   \item \bl{$A \,\text{sends}\, B : \{msg\}_{K^{new}_{AB}}$}\;\;\;\;\bl{$I$} can read it also
- \end{itemize}	
- \end{minipage}
-
-  \end{frame}}
-  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
-     
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}[c]
-
-A Man-in-the-middle attack in real life:
-
-\begin{itemize}
-\item the card only says yes or no to the terminal if the PIN is correct
-\item trick the card in thinking transaction is verified by signature
-\item trick the terminal in thinking the transaction was verified by PIN
-\end{itemize}
-
-\begin{minipage}{1.1\textwidth}
-\begin{center}
-\mbox{}\hspace{-6mm}\includegraphics[scale=0.5]{pics/chip-attack.png}
-\includegraphics[scale=0.3]{pics/chipnpinflaw.png}
-\end{center}
-\end{minipage}
-
-\end{frame}}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}[c]
-\frametitle{Problems with EMV}
-
-\begin{itemize}
-\item it is a wrapper for many protocols
-\item specification by consensus (resulted unmanageable complexity)
-\item its specification is 700 pages in English plus 2000+ pages for testing, additionally some 
-further parts are secret
-\item other attacks have been found
-
-\item one solution might be to require always online verification of the PIN with the bank
-\end{itemize}
-
-\end{frame}}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
-
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}[c]
-\frametitle{\begin{tabular}{c}Problems with WEP (Wifi)\end{tabular}}
-
-\begin{itemize}
-\item a standard ratified in 1999
-\item the protocol was designed by a committee not including cryptographers
-\item it used the RC4 encryption algorithm which is a stream cipher requiring a unique nonce
-\item WEP did not allocate enough bits for the nonce
-\item for authenticating packets it used CRC checksum which can be easily broken
-\item the network password was used to directly encrypt packages (instead of a key negotiation protocol)\bigskip
-\item encryption was turned off by default
-\end{itemize}
-
-\end{frame}}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
-
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}[c]
-\frametitle{Protocols are Difficult}
-
-\begin{itemize}
-\item even the systems designed by experts regularly fail\medskip
-\item try to make everything explicit (you need to authenticate all data you might rely on)\medskip
-\item the one who can fix a system should also be liable for the losses\medskip
-\item cryptography is often not {\bf the} answer\bigskip\bigskip  
-\end{itemize}
-
-logic is one way protocols are studied in academia
-(you can use computers to search for attacks)
-
-\end{frame}}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}[c]
-\frametitle{Public-Key Infrastructure}
-
-\begin{itemize}
-\item the idea is to have a certificate authority (CA)
-\item you go to the CA to identify yourself
-\item CA: ``I, the CA, have verified that public key \bl{$P^{pub}_{Bob}$} belongs to Bob''\bigskip
-\item CA must be trusted by everybody
-\item What happens if CA issues a false certificate? Who pays in case of loss? (VeriSign 
-explicitly limits liability to \$100.)
-\end{itemize}
-
-\end{frame}}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
-
-
-
-
-
-
-     
-\end{document}
-
-%%% Local Variables:  
-%%% mode: latex
-%%% TeX-master: t
-%%% End: 
-




