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+
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% beamer stuff +
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\renewcommand{\slidecaption}{APP 02, King's College London, 1 October 2013}+
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+
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%Bank vs Voting+
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%http://www.parliament.vic.gov.au/images/stories/committees/emc/2010_Election/submissions/13_VTeague_EMC_Inquiry_No.6.pdf+
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+
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% first cyber attack+
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%http://investigations.nbcnews.com/_news/2013/03/18/17314818-cyberattack-on-florida-election-is-first-known-case-in-us-experts-say+
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+
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\begin{document}+
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+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
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\mode<presentation>{+
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\begin{frame}<1>[t]+
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\frametitle{%+
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  \begin{tabular}{@ {}c@ {}}+
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  \\+
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  \LARGE Access Control and \\[-3mm] +
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  \LARGE Privacy Policies (2)\\[-6mm] +
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  \end{tabular}}\bigskip\bigskip\bigskip+
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+
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\normalsize+
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  \begin{center}+
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  \begin{tabular}{ll}+
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  Email:  & christian.urban at kcl.ac.uk\\+
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  Office: & S1.27 (1st floor Strand Building)\\+
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  Slides: & KEATS (also homework is there)\\+
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  \end{tabular}+
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  \end{center}+
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+
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\end{frame}}+
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 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%     +
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
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\mode<presentation>{+
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\begin{frame}[c]+
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\frametitle{\begin{tabular}{c}This Course is about\\[-2mm]  ``Satan's Computer''\end{tabular}}+
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+
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Ross Anderson and Roger Needham wrote:\bigskip+
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+
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\begin{tikzpicture}+
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\draw (0,0) node[inner sep=2mm,fill=cream, ultra thick, draw=red, rounded corners=2mm] +
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{\normalsize\color{darkgray}+
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\begin{minipage}{10cm}\raggedright\small+
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``In effect, our task is to program a computer which gives +
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answers which are subtly and maliciously wrong at the most +
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inconvenient possible moment\ldots{} we hope that the lessons +
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learned from programming Satan's computer may be helpful +
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in tackling the more common problem of programming Murphy's.''+
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\end{minipage}};+
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\end{tikzpicture}\\[30mm]+
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+
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\only<2>{+
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\begin{textblock}{11}(2,12)+
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\begin{tabular}{c}+
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\includegraphics[scale=0.12]{pics/ariane.jpg}\\[-2mm]+
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\footnotesize Murphy's computer+
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\end{tabular}+
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\begin{tabular}{c}+
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\includegraphics[scale=0.15]{pics/mobile.jpg}\;+
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\includegraphics[scale=0.06]{pics/pinsentry.jpg}\\[-2mm]+
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\footnotesize Satan's computers+
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\end{tabular}+
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\end{textblock}}+
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+
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\end{frame}}+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   +
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+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
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\mode<presentation>{+
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\begin{frame}[c]+
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\frametitle{\Large\begin{tabular}{c}User-Tracking Without Cookies\end{tabular}}+
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+
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Can you track a user {\bf without}:+
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+
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\begin{itemize}+
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\item Cookies+
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\item Javascript+
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\item LocalStorage/SessionStorage/GlobalStorage+
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\item Flash, Java or other plugins+
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\item Your IP address or user agent string+
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\item Any methods employed by Panopticlick\\+
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\mbox{}\hfill $\rightarrow$ \textcolor{blue}{\url{https://panopticlick.eff.org/}}+
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\end{itemize}+
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+
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Even when you disabled cookies entirely, have Javascript turned off and use a VPN service.\\\pause+
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And numerous sites already use it (Google).+
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+
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\end{frame}}+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   +
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
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\mode<presentation>{+
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\frametitle{\begin{tabular}{c}Web-Protocol\end{tabular}}+
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\begin{textblock}{1}(4.2,13.9)+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   +
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
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\mode<presentation>{+
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\begin{frame}[c]+
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\frametitle{Today's Lecture}+
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\begin{center}+
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\begin{tabular}{cc}+
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\large online banking  & \hspace{6mm}\large e-voting\\+
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\textcolor{gray}{solved} & \hspace{6mm}\textcolor{gray}{unsolved}\\+
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\end{tabular}+
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\end{center}+
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+
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\end{frame}}+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%  +
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
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\mode<presentation>{+
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\begin{frame}[t]+
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\frametitle{\begin{tabular}{@ {}c@ {}}Voting as Security Problem\end{tabular}}+
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+
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What are the security requirements of a voting system?\bigskip+
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+
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\begin{itemize}+
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\item<2->Integrity +
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\item<3->Ballot Secrecy+
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\item<5->Voter Authentication+
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\item<6->Enfranchisement+
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\item<7->Availability+
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\end{itemize}+
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+
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\only<2>{+
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\begin{textblock}{5.5}(8,5)+
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\begin{tikzpicture}+
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\draw (0,0) node[inner sep=2mm,fill=cream, ultra thick, draw=red, rounded corners=2mm, text centered] +
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{\small+
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\begin{minipage}{5cm}\raggedright+
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\begin{center}+
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\begin{minipage}{4.5cm}+
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\begin{itemize}+
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\item The outcome matches with the voters' intend.+
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\item There might be gigantic sums at stake and need to be defended against.+
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\end{itemize}+
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\end{minipage}+
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\end{center}+
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\end{minipage}};+
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\end{tikzpicture}+
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\end{textblock}}+
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+
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\only<4>{+
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\begin{textblock}{5.5}(8,5)+
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\begin{tikzpicture}+
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\draw (0,0) node[inner sep=2mm,fill=cream, ultra thick, draw=red, rounded corners=2mm, text centered] +
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{\small+
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\begin{minipage}{5cm}\raggedright+
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\begin{center}+
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\begin{minipage}{4.5cm}+
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\begin{itemize}+
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\item Nobody can find out how you voted.+
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\item (Stronger) Even if you try, you cannot prove how you voted.+
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\end{itemize}+
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\end{minipage}+
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\end{center}+
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\end{minipage}};+
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\end{tikzpicture}+
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\end{textblock}}+
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+
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\only<5>{+
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\begin{textblock}{5.5}(8,5)+
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\begin{tikzpicture}+
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\draw (0,0) node[inner sep=2mm,fill=cream, ultra thick, draw=red, rounded corners=2mm, text centered] +
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{\small+
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\begin{minipage}{5cm}\raggedright+
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\begin{center}+
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\begin{minipage}{4.5cm}+
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\begin{itemize}+
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\item Only authorised voters can vote up to the permitted number of votes.+
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\end{itemize}+
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\end{minipage}+
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\end{center}+
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\end{minipage}};+
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\end{tikzpicture}+
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\end{textblock}}+
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+
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\only<6>{+
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\begin{textblock}{5.5}(8,5)+
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\begin{tikzpicture}+
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\draw (0,0) node[inner sep=2mm,fill=cream, ultra thick, draw=red, rounded corners=2mm, text centered] +
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{\small+
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\begin{minipage}{5cm}\raggedright+
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\begin{center}+
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\begin{minipage}{4.5cm}+
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\begin{itemize}+
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\item Authorised voters should have the opportunity to vote.+
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\end{itemize}+
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\end{minipage}+
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\end{center}+
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\end{minipage}};+
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\end{tikzpicture}+
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\end{textblock}}+
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+
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\only<7>{+
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\begin{textblock}{5.5}(8,5)+
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\begin{tikzpicture}+
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\draw (0,0) node[inner sep=2mm,fill=cream, ultra thick, draw=red, rounded corners=2mm, text centered] +
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{\small+
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\begin{minipage}{5cm}\raggedright+
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\begin{center}+
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\begin{minipage}{4.5cm}+
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\begin{itemize}+
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\item The voting system should accept all authorised votes and produce results in a timely manner.+
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\end{itemize}+
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\end{minipage}+
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\end{center}+
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\end{minipage}};+
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\end{tikzpicture}+
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\end{textblock}}+
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+
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\end{frame}}+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   +
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+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
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\mode<presentation>{+
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\begin{frame}[t]+
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\frametitle{\begin{tabular}{@ {}c@ {}}Problems with Voting\end{tabular}}+
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+
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+
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\begin{center}\large+
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\begin{tabular}{rcl}+
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Integrity & vs. & Ballot Secrecy\bigskip\\+
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Authentication & vs. &Enfranchisement   +
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\end{tabular}+
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\end{center}\bigskip\bigskip\pause+
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+
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Further constraints:+
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+
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\begin{itemize}+
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\item costs+
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\item accessibility+
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\item convenience+
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\item intelligibility +
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\end{itemize}+
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\end{frame}}+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   +
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+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
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\mode<presentation>{+
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\begin{frame}[t]+
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\frametitle{\begin{tabular}{@ {}c@ {}}Traditional Ballot Boxes\end{tabular}}+
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+
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+
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\begin{center}+
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\includegraphics[scale=2.5]{pics/ballotbox.jpg}+
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\end{center}\pause\bigskip+
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+
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they need a ``protocol''+
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+
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+
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\end{frame}}+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   +
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+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
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\mode<presentation>{+
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\begin{frame}[t]+
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\frametitle{\begin{tabular}{@ {}c@ {}}E-Voting\end{tabular}}+
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+
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+
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\begin{itemize}+
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\item The Netherlands between 1997 - 2006 had electronic voting machines\\+
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\textcolor{gray}{(hacktivists had found: they can be hacked and also emitted radio signals revealing how you voted)}+
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+
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\item Germany had used them in pilot studies\\ +
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\textcolor{gray}{(in 2007 a law suit has reached the highest court and it rejected electronic voting+
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on the grounds of not being understandable by the general public)}+
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+
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\item UK used optical scan voting systems in a few polls+
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\end{itemize}+
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\end{frame}}+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   +
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+
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\mode<presentation>{+
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\begin{frame}[t]+
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\frametitle{\begin{tabular}{@ {}c@ {}}E-Voting\end{tabular}}+
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+
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\mbox{}\\[-12mm]+
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\begin{itemize}+
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\item US used mechanical machines since the 30s, later punch cards, now DREs and +
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optical scan voting machines+
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+
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\item Estonia used in 2007 the Internet for national elections +
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\textcolor{gray}{(there were earlier pilot studies in other countries)}+
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+
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\item India uses e-voting devices  since at least 2003\\+
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\textcolor{gray}{(``keep-it-simple'' machines produced by a government owned company)}+
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+
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\item South Africa used software for its tallying in the 1993 elections (when Nelson Mandela was elected)+
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\textcolor{gray}{(they found the tallying software was rigged, but they were able to tally manually)}+
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\end{itemize}+
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\end{frame}}+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   +
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+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
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\mode<presentation>{+
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\begin{frame}[t]+
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\frametitle{\begin{tabular}{@ {}c@ {}}A Brief History of Voting\end{tabular}}+
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+
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+
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\begin{itemize}+
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\item Athenians+
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\begin{itemize}+
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\item show of hands+
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\item ballots on pieces of pottery+
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\item different colours of stones+
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\item ``facebook''-like authorisation +
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\end{itemize}\bigskip+
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+
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\textcolor{gray}{problems with vote buying / no ballot privacy}\bigskip+
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+
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+
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\item French Revolution and the US Constitution got things ``started'' with +
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paper ballots (you first had to bring your own; later they were pre-printed by parties)+
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\end{itemize}+
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\end{frame}}+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   +
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+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
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\mode<presentation>{+
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\begin{frame}[t]+
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\frametitle{\begin{tabular}{@ {}c@ {}}Ballot Boxes\end{tabular}}+
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+
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Security policies involved with paper ballots:+
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+
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\begin{enumerate}+
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\item you need to check that the ballot box is empty at the start of the poll / no false bottom (to prevent ballot stuffing)+
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\item you need to guard the ballot box during the poll until counting+
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\item tallied by a team at the end of the poll (independent observers) +
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\end{enumerate}+
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+
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\begin{center}+
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\includegraphics[scale=1.5]{pics/ballotbox.jpg}+
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\end{center}+
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+
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+
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\end{frame}}+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   +
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+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   +
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\mode<presentation>{+
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\begin{frame}[c]+
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+
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Which security requirements do paper ballots satisfy better than voice voting?\bigskip+
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+
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\begin{itemize}+
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\item Integrity+
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\item Enfranchisement+
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\item Ballot secrecy+
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\item Voter authentication+
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\item Availability+
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\end{itemize}+
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+
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\end{frame}}+
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+
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+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
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\mode<presentation>{+
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\begin{frame}[t]+
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\frametitle{\begin{tabular}{@ {}c@ {}}Paper Ballots\end{tabular}}+
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+
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What can go wrong with paper ballots?+
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+
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\only<2>{+
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\begin{center}+
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\includegraphics[scale=0.8]{pics/tweet.jpg}\\+
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\footnotesize William M.~Tweed, US Politician in 1860's\\+
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``As long as I count the votes, what are you going to do about it?''+
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\end{center}}+
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+
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\only<3>{+
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\medskip+
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\begin{center}+
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\begin{minipage}{10cm}+
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{\bf Chain Voting Attack}+
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\begin{enumerate}+
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\item you obtain a blank ballot and fill it out as you want+
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\item you give it to a voter outside the polling station+
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\item voter receives a new blank ballot+
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\item voter submits prefilled ballot+
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\item voter gives blank ballot to you, you give money+
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\item goto 1+
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\end{enumerate}+
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\end{minipage}+
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\end{center}+
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}+
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+
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\end{frame}}+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   +
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
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\mode<presentation>{+
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\begin{frame}[t]+
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\frametitle{\begin{tabular}{@ {}c@ {}}Mechanical Voting Machines\end{tabular}}+
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+
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\begin{itemize}+
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\item<1-> Lever Voting Machines (ca.~1930 - 1990)+
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\only<1>{+
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\begin{center}+
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\includegraphics[scale=0.56]{pics/leavermachine.jpg}+
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\end{center}+
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}+
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\item<2->Punch Cards (ca.~1950 - 2000)+
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\only<2>{+
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\begin{center}+
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\includegraphics[scale=0.5]{pics/punchcard1.jpg}\;\;+
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\includegraphics[scale=0.46]{pics/punchcard2.jpg}+
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\end{center}+
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}+
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\end{itemize}+
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+
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+
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+
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\end{frame}}+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   +
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+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
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\mode<presentation>{+
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\begin{frame}[t]+
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\frametitle{\begin{tabular}{@ {}c@ {}}Electronic Voting Machines\end{tabular}}+
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+
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\begin{center}+
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\begin{tabular}{c}+
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\includegraphics[scale=0.45]{pics/dre1.jpg}\; +
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\includegraphics[scale=0.40]{pics/dre2.jpg}\\\hline\\+
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\includegraphics[scale=0.5]{pics/opticalscan.jpg} +
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\end{tabular}+
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\end{center}+
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+
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\only<1->{+
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\begin{textblock}{5.5}(1,4)+
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DREs+
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\end{textblock}}+
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\only<1->{+
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\begin{textblock}{5.5}(1,11)+
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Optical Scan+
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\end{textblock}}+
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+
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\only<2>{+
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\begin{textblock}{5.5}(0.5,14.5)+
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all are computers+
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\end{textblock}}+
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+
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\end{frame}}+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   +
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+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
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\mode<presentation>{+
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\begin{frame}[c]+
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\frametitle{\begin{tabular}{@ {}c@ {}}DREs\end{tabular}}+
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+
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Direct-recording electronic voting machines\\ +
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(votes are recorded for example on memory cards)+
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+
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typically touchscreen machines+
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+
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usually no papertrail+
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+
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\begin{center}+
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\includegraphics[scale=0.56]{pics/dre1.jpg}+
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\end{center}+
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+
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+
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\end{frame}}+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   +
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+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
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\mode<presentation>{+
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\begin{frame}[c]+
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\frametitle{\begin{tabular}{@ {}c@ {}}Diebold Machines\end{tabular}}+
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+
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The work by J.~Alex Halderman:+
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+
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\begin{itemize}+
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\item acquired a machine from an anonymous source\medskip+
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\item they try to keep secret the source code running the machine\medskip\pause+
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+
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\item first reversed-engineered the machine (extremely tedious)+
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\item could completely reboot the machine and even install a virus that infects other Diebold machines+
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\item obtained also the source code for other machines+
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\end{itemize}+
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+
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\end{frame}}+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   +
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+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
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\mode<presentation>{+
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\begin{frame}[c]+
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\frametitle{\begin{tabular}{@ {}c@ {}}Diebold Machines\end{tabular}}+
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+
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What could go wrong?\pause \;\;Failure-in-depth.\bigskip\pause+
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+
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A non-obvious problem:+
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+
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\begin{itemize}+
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\item you can nowadays get old machines, which still store old polls+
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+
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\item the paper ballot box needed to be secured during the voting until counting;+
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e-voting machines need to be secured during the entire life-time  +
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\end{itemize}+
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+
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\end{frame}}+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   +
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+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
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\mode<presentation>{+
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\begin{frame}[c]+
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\frametitle{\begin{tabular}{@ {}c@ {}}Paper Trail\end{tabular}}+
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+
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Conclusion:\\ Any electronic solution should have a paper trail.+
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+
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\begin{center}+
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\begin{tabular}{c}+
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\includegraphics[scale=0.5]{pics/opticalscan.jpg} +
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\end{tabular}+
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\end{center}\pause+
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+
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You still have to solve problems about+
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voter registration, voter authentication, guarding against tampering+
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+
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\end{frame}}+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   +
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+
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+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
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\mode<presentation>{+
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\begin{frame}[c]+
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\frametitle{\begin{tabular}{@ {}c@ {}}E-Voting in India\end{tabular}}+
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+
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Their underlying engineering principle is ``keep-it-simple'':+
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+
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\begin{center}+
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\begin{tabular}{c}+
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\includegraphics[scale=1.05]{pics/indiaellection.jpg}\;\;+
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\includegraphics[scale=0.40]{pics/india1.jpg}+
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\end{tabular}+
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\end{center}\medskip\pause+
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+
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Official claims: ``perfect'', ``tamperproof'', ``no need for technical improvements'' , ``infallible'' +
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\end{frame}}+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   +
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+
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+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
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\mode<presentation>{+
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\begin{frame}<1-3>[c]+
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\frametitle{\begin{tabular}{@ {}c@ {}}Lessons Learned\end{tabular}}+
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+
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\begin{itemize}+
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\item keep a paper trail and design your system to keep this secure\medskip+
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\item make the software open source (avoid security-by-obscurity)\\+
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{\small\mbox{}\hfill source code for Estonian e-vote included\\ +
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\mbox{}\hfill\textcolor{blue}{\url{http://goo.gl/oRMHAI}}}\medskip+
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\item have a simple design in order to minimise the attack surface+
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\end{itemize}+
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+
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\only<2>{+
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\begin{textblock}{9}(3.4,7)+
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\begin{tikzpicture}+
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\draw (0,0) node[inner sep=2mm,fill=cream, ultra thick, draw=red, rounded corners=2mm] +
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{\normalsize\color{darkgray}+
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\begin{minipage}{9cm}\consolas\small+
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def analyze(ik, vote, votebox):\\+
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\\+
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    \#   TODO: implement security checks\\+
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    \#   such as verifying the correct size\\+
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    \#   of the encrypted vote\\+
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\\+
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    return []+
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\end{minipage}};+
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\end{tikzpicture}+
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\end{textblock}}+
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+
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\end{frame}}+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   +
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+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
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\mode<presentation>{+
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\begin{frame}[c]+
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\frametitle{Online Banking vs.~E-Voting}+
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+
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\begin{itemize}+
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\item online banking: if fraud occurred you try to identify who did what (somebody's account got zero)\bigskip+
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\item e-voting: some parts can be done electronically, but not the actual voting (final year project: online voting)+
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\end{itemize}+
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+
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+
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\end{frame}}+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%  +
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+
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+
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+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
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\mode<presentation>{+
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\begin{frame}[c]+
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+
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\begin{center}+
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\includegraphics[scale=0.56]{pics/Voting1.png}+
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\end{center}+
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+
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+
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\end{frame}}+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   +
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+
−
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
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\mode<presentation>{+
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\begin{frame}[c]+
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+
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\begin{center}+
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\includegraphics[scale=0.56]{pics/Voting2.png}+
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\end{center}+
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+
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+
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\end{frame}}+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   +
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+
−
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
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\mode<presentation>{+
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\begin{frame}[c]+
−
+
−
\begin{center}+
−
\includegraphics[scale=0.56]{pics/Voting3.png}+
−
\end{center}+
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+
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+
−
\end{frame}}+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   +
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+
−
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
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\mode<presentation>{+
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\begin{frame}[c]+
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+
−
\begin{center}+
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\includegraphics[scale=0.56]{pics/Voting4.png}+
−
\end{center}+
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+
−
+
−
\end{frame}}+
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   +
−
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
−
\mode<presentation>{+
−
\begin{frame}[c]+
−
\frametitle{Unix-Style Access Control}+
−
+
−
How to do access control? In Unix you have+
−
+
−
\begin{itemize}+
−
\item you have users and you have groups/roles:+
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+
−
\item some special roles: root+
−
\end{itemize}+
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+
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  +
−
\end{frame}}+
−
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   +
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+
−
+
−
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
−
\mode<presentation>{+
−
\begin{frame}[c]+
−
\frametitle{Unix-Style Access Control}+
−
+
−
\begin{itemize}+
−
\item Q: ``I am using Windows. Why should I care?'' \\ A: In Windows you have similar AC:+
−
+
−
\begin{center}+
−
\begin{tabular}{l}+
−
administrators group\\ +
−
\hspace{5mm}(has complete control over the machine)\\+
−
authenticated users\\+
−
server operators\\+
−
power users\\+
−
network configuration operators\\+
−
\end{tabular}+
−
\end{center}\medskip+
−
+
−
\item Modern versions of Windows have more fine-grained AC than Unix; they do not have a setuid bit, but+
−
have \texttt{runas} (asks for a password).\pause+
−
+
−
\item OS-provided access control can \alert{\bf add} to your+
−
security.+
−
\end{itemize}+
−
+
−
  +
−
\end{frame}}+
−
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   +
−
+
−
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
−
\mode<presentation>{+
−
\begin{frame}[c]+
−
\frametitle{\begin{tabular}{c}Network Applications:\\[-1mm] Privilege Separation\end{tabular}}+
−
+
−
+
−
\begin{center}+
−
  \begin{tikzpicture}[scale=1]+
−
  +
−
  \draw[line width=1mm] (-.3, 0) rectangle (1.5,2);+
−
  \draw (4.7,1) node {Internet};+
−
  \draw (-2.7,1.7) node {\footnotesize Application};+
−
  \draw (0.6,1.7) node {\footnotesize Interface};+
−
  \draw (0.6,-0.4) node {\footnotesize \begin{tabular}{c}unprivileged\\[-1mm] process\end{tabular}};+
−
  \draw (-2.7,-0.4) node {\footnotesize \begin{tabular}{c}privileged\\[-1mm] process\end{tabular}};+
−
  +
−
  \draw[line width=1mm] (-1.8, 0) rectangle (-3.6,2);+
−
+
−
  \draw[white] (1.7,1) node (X) {};+
−
  \draw[white] (3.7,1) node (Y) {};+
−
  \draw[red, <->, line width = 2mm] (X) -- (Y);+
−
 +
−
  \draw[red, <->, line width = 1mm] (-0.6,1) -- (-1.6,1);+
−
  \end{tikzpicture}+
−
\end{center}+
−
+
−
\begin{itemize}+
−
\item the idea is make the attack surface smaller and +
−
mitigate the consequences of an attack+
−
\end{itemize}+
−
+
−
+
−
\end{frame}}+
−
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%     +
−
+
−
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
−
\mode<presentation>{+
−
\begin{frame}[c]+
−
\frametitle{Lessons from Access Control}+
−
+
−
Not just restricted to Unix:+
−
+
−
\begin{itemize}+
−
\item if you have too many roles (i.e.~too finegrained AC), then +
−
	hierarchy is too complex\\+
−
	\textcolor{gray}{you invite situations like\ldots let's be root}\bigskip+
−
+
−
\item you can still abuse the system\ldots+
−
+
−
\end{itemize}+
−
+
−
\end{frame}}+
−
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   +
−
+
−
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
−
\mode<presentation>{+
−
\begin{frame}[c]+
−
\frametitle{\begin{tabular}{@ {}c@ {}}A ``Cron''-Attack\end{tabular}}+
−
+
−
The idea is to trick a privileged person to do something on your behalf:+
−
+
−
\begin{itemize}+
−
\item root:\\\texttt{rm /tmp/*/*}\bigskip\bigskip\pause+
−
+
−
\footnotesize+
−
\begin{minipage}{1.1\textwidth}+
−
\textcolor{gray}{the shell behind the scenes:}\\+
−
\textcolor{gray}{\texttt{rm /tmp/dir$_1$/file$_1$ /tmp/dir$_1$/file$_2$ /tmp/dir$_2$/file$_1$ \ldots}}\bigskip\\+
−
+
−
\textcolor{gray}{this takes time}+
−
\end{minipage}+
−
\end{itemize}+
−
+
−
+
−
\end{frame}}+
−
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   +
−
+
−
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+
−
\mode<presentation>{+
−
\begin{frame}[c]+
−
\frametitle{\begin{tabular}{@ {}c@ {}}A ``Cron''-Attack\end{tabular}}+
−
+
−
\begin{enumerate}+
−
\item attacker \textcolor{gray}{(creates a fake passwd file)}\\ +
−
\texttt{mkdir /tmp/a; cat > /tmp/a/passwd}\medskip+
−
\item root \textcolor{gray}{(does the daily cleaning)}\\+
−
\texttt{rm /tmp/*/*}\medskip\\+
−
\hspace{2cm}\textcolor{gray}{\small records that \texttt{/tmp/a/passwd}}\\ +
−
\hspace{2cm}\textcolor{gray}{\small should be deleted, but does not do it yet}\medskip\\+
−
+
−
\item attacker \textcolor{gray}{(meanwhile deletes the fake passwd file, and establishes a link to +
−
the real passwd file)}\\+
−
\texttt{rm /tmp/a/passwd; rmdir /tmp/a;}\\\texttt{ln -s /etc /tmp/a}\\+
−
\item root now deletes  the real passwd file+
−
\end{enumerate}+
−
+
−
\only<2>{+
−
\begin{textblock}{11}(2,5)+
−
\begin{tikzpicture}+
−
\draw (0,0) node[inner sep=2mm,fill=cream, ultra thick, draw=red, rounded corners=2mm] +
−
{\normalsize\color{darkgray}+
−
\begin{minipage}{9cm}\raggedright+
−
To prevent this kind of attack, you need additional+
−
policies (don't do such operations as root).+
−
\end{minipage}};+
−
\end{tikzpicture}+
−
\end{textblock}}+
−
+
−
\end{frame}}+
−
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   +
−
+
−
+
−
\end{document}+
−
+
−
%%% Local Variables:  +
−
%%% mode: latex+
−
%%% TeX-master: t+
−
%%% End: +
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+
−