--- a/hw04.tex	Tue Oct 16 14:42:43 2012 +0100
+++ b/hw04.tex	Mon Oct 22 11:42:45 2012 +0100
@@ -1,35 +1,43 @@
 \documentclass{article}
 \usepackage{charter}
 \usepackage{hyperref}
+\usepackage{amssymb}
 
 \begin{document}
 
 \section*{Homework 4}
 
 \begin{enumerate}
-\item What is bad about security-by-obscurity?
-
-\item In which of the following situations can the access control mechanism of Unix
-file permissions be used?
+\item Voice voting is the method of casting a vote in the `open air' for everyone
+present to hear. Which of the following security requirements do paper ballots 
+satisfy better than voice voting? Check all that apply and give a brief explanation 
+for your decision.
 
 \begin{itemize}
-\item[(a)] Alice wants to have her files readable, except for her office mates.
-\item[(b)] Bob and Sam want to share some secret files.
-\item[(c)] Root wants some of her files to be public.
+\item[$\Box$] Integrity\bigskip\bigskip
+\item[$\Box$] Enfranchisement\bigskip\bigskip
+\item[$\Box$] Ballot secrecy\bigskip\bigskip
+\item[$\Box$] Voter authentication\bigskip\bigskip
+\item[$\Box$] Availability\bigskip\bigskip
 \end{itemize}
 
-\item What should the architecture of a network application under Unix 
-be that processes potentially hostile data?
 
-\item How can you exploit the fact that every night root has a cron
-job that deletes the files in \texttt{/tmp}?
+\item Explain how an attacker can use chain voting in order to influence the outcome of a 
+poll using paper ballots. 
+
+\item Which of the following mechanisms help with defending against chain voting? Check all 
+that apply. Give a brief reason for each defence that mitigates chain voting attacks.
 
-\item What does it mean that the program \texttt{passwd} has the \texttt{setuid}
-bit set? Why is this necessary?
+\begin{itemize}
+\item[$\Box$] Using a glass ballot box to make it clear there are no ballots in the box before the start of the election.
+\item[$\Box$] Distributing ballots publicly before the election.
+\item[$\Box$] Checking that a voter's ID (drivers license, passport) matches the voter.
+\item[$\Box$] Each ballot has a unique ID. When a voter is given a ballot, the ID is recorded. When the voter submits his or her ballot, this ID is checked against the record.
+\end{itemize}
 
-\item (Optional) Imagine you want to atack a 
 \end{enumerate}
 
+
 \end{document}
 
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