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% beamer stuff 

\renewcommand{\slidecaption}{APP 02, King's College London}

%Bank vs Voting

%http://www.parliament.vic.gov.au/images/stories/committees/emc/2010_Election/submissions/13_VTeague_EMC_Inquiry_No.6.pdf

% first cyber attack

%http://investigations.nbcnews.com/_news/2013/03/18/17314818-cyberattack-on-florida-election-is-first-known-case-in-us-experts-say

\begin{document}

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\begin{frame}[t]

\frametitle{%

  \begin{tabular}{@ {}c@ {}}

  \\

  \LARGE Access Control and \\[-3mm] 

  \LARGE Privacy Policies (2)\\[-6mm] 

  \end{tabular}}\bigskip\bigskip\bigskip

\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}

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\begin{frame}[c]

\frametitle{\begin{tabular}{c}This Course is about\\[-2mm]  ``Satan's Computer''\end{tabular}}

Ross Anderson and Roger Needham wrote:\bigskip

\begin{bubble}[10cm]

\small

``In effect, our task is to program a computer which gives 

answers which are subtly and maliciously wrong at the most 

inconvenient possible moment\ldots{} we hope that the lessons 

learned from programming Satan's computer may be helpful 

in tackling the more common problem of programming Murphy's.''

\end{bubble}\\[30mm]

\only<2>{

\begin{tabular}{c}

\includegraphics[scale=0.12]{pics/ariane.jpg}\\[-2mm]

\footnotesize Murphy's computer

\end{tabular}

\begin{tabular}{c}

\includegraphics[scale=0.15]{pics/mobile.jpg}\;

\includegraphics[scale=0.06]{pics/pinsentry.jpg}\\[-2mm]

\footnotesize Satan's computers

\end{tabular}

\end{textblock}}

\end{frame}

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\begin{frame}[c]

\frametitle{Defence in Depth}

\pcode{urbanc:$6$3WWbKfr1$4vblknvGr6FcDeF92R5xFn3mskfdnEn...:...}

\end{center}

\begin{itemize}

\item hashes help when password databases are leaked

\item salts help with protecting against dictionary attacks

\end{itemize}

\end{frame}

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\begin{frame}[c]

\frametitle{Today's Lecture}

\begin{center}

\end{tabular}

\end{center}

\end{frame}

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\mode<presentation>{

\begin{frame}[t]

\frametitle{\begin{tabular}{@ {}c@ {}}Voting as Security Problem\end{tabular}}

What are the security requirements of a voting system?\bigskip

\begin{itemize}

\item<2->Integrity 

\item<3->Ballot Secrecy

\item<5->Voter Authentication

\item<6->Enfranchisement

\item<7->Availability

\end{itemize}

\only<2>{

\begin{textblock}{5.5}(8,5)

\begin{center}

\begin{minipage}{4.5cm}

\begin{itemize}

\item The outcome matches with the voters' intend.

\item There might be gigantic sums at stake and need to be defended against.

\end{itemize}

\end{minipage}

\end{center}

\end{textblock}}

\only<4>{

\begin{textblock}{5.5}(8,5)

\begin{center}

\begin{minipage}{4.5cm}

\begin{itemize}

\item Nobody can find out how you voted.

\item (Stronger) Even if you try, you cannot prove how you voted.

\end{itemize}

\end{minipage}

\end{center}

\end{textblock}}

\only<5>{

\begin{textblock}{5.5}(8,5)

\begin{center}

\begin{minipage}{4.5cm}

\begin{itemize}

\item Only authorised voters can vote up to the permitted number of votes.

\end{itemize}

\end{minipage}

\end{center}

\end{textblock}}

\only<6>{

\begin{textblock}{5.5}(8,5)

\begin{center}

\begin{minipage}{4.5cm}

\begin{itemize}

\item Authorised voters should have the opportunity to vote.

\end{itemize}

\end{minipage}

\end{center}

\end{textblock}}

\only<7>{

\begin{textblock}{5.5}(8,5)

\begin{center}

\begin{minipage}{4.5cm}

\begin{itemize}

\item The voting system should accept all authorised votes and produce results in a timely manner.

\end{itemize}

\end{minipage}

\end{center}

\end{textblock}}

\end{frame}}

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\begin{frame}[t]

\frametitle{\begin{tabular}{@ {}c@ {}}Problems with Voting\end{tabular}}

\begin{center}\large

\begin{tabular}{rcl}

Integrity & vs. & Ballot Secrecy\bigskip\\

Authentication & vs. &Enfranchisement   

\end{tabular}

\end{center}\bigskip\bigskip\pause

Further constraints:

\begin{itemize}

\item costs

\item accessibility

\item convenience

\item intelligibility 

\end{itemize}

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\begin{frame}[t]

\begin{center}

\includegraphics[scale=2.5]{pics/ballotbox.jpg}

\end{center}\pause\bigskip

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\begin{frame}[t]

\begin{itemize}

\end{itemize}

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\begin{frame}[t]

\end{itemize}

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\mode<presentation>{

\begin{frame}[t]

\frametitle{\begin{tabular}{@ {}c@ {}}A Brief History of Voting\end{tabular}}

\begin{itemize}

\item Athenians

\begin{itemize}

\item show of hands

\item ballots on pieces of pottery

\item different colours of stones

\item ``facebook''-like authorisation 

\end{itemize}\bigskip

\textcolor{gray}{problems with vote buying / no ballot privacy}\bigskip

\item French Revolution and the US Constitution got things ``started'' with 

paper ballots (you first had to bring your own; later they were pre-printed by parties)

\end{itemize}

\end{frame}}

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\mode<presentation>{

\begin{frame}[t]

\frametitle{\begin{tabular}{@ {}c@ {}}Ballot Boxes\end{tabular}}

\begin{enumerate}

\item you need to check that the ballot box is empty at the start of the poll / no false bottom (to prevent ballot stuffing)

\item you need to guard the ballot box during the poll until counting

\item tallied by a team at the end of the poll (independent observers) 

\end{enumerate}

\begin{center}

\includegraphics[scale=1.5]{pics/ballotbox.jpg}

\end{center}

\end{frame}}

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\begin{frame}[c]

Which security requirements do paper ballots satisfy better than voice voting?\bigskip

\begin{itemize}

\item Integrity

\item Enfranchisement

\item Ballot secrecy

\item Voter authentication

\item Availability

\end{itemize}

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\mode<presentation>{

\begin{frame}[t]

\frametitle{\begin{tabular}{@ {}c@ {}}Paper Ballots\end{tabular}}

What can go wrong with paper ballots?

\only<2>{

\begin{center}

\includegraphics[scale=0.8]{pics/tweet.jpg}\\

\footnotesize William M.~Tweed, US Politician in 1860's\\

``As long as I count the votes, what are you going to do about it?''

\end{center}}

\only<3>{

\medskip

\begin{center}

\begin{minipage}{10cm}

{\bf Chain Voting Attack}

\begin{enumerate}

\item you obtain a blank ballot and fill it out as you want

\item you give it to a voter outside the polling station

\item voter receives a new blank ballot

\item voter submits prefilled ballot

\item voter gives blank ballot to you, you give money

\item goto 1

\end{enumerate}

\end{minipage}

\end{center}

}

\end{frame}}

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\begin{frame}[t]

\begin{itemize}