diff -r e1e314c1bb61 -r efcac3016613 hws/hw07.tex --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/hws/hw07.tex Mon Sep 23 17:39:31 2013 +0100 @@ -0,0 +1,40 @@ +\documentclass{article} +\usepackage{charter} +\usepackage{hyperref} +\usepackage{amssymb} +\usepackage{proof} + +\begin{document} + +\section*{Homework 7} + +\begin{enumerate} +\item Suppose a judgement is of the form: +\begin{center} +$Alice\;\textit{says}\;S \wedge Bob\;\textit{says}\;S \vdash Bob\;\textit{says}\;S \wedge Alice\;\textit{says}\;S$ +\end{center} + +Assume you want to use the inference rule + +\begin{center} +\mbox{\infer{\Gamma \vdash F_1 \wedge F_2}{\Gamma \vdash F_1 & \Gamma \vdash F_2}} +\end{center} + +for constructing a proof of the judgement. What do the premises look like? + +\item The informal meaning of the formula \mbox{$P\;\mapsto\;Q$} is `$P$ speaks for +$Q$'. Give a definition for this formula in terms of $\textit{says}$. + +\item In Unix, what should be the general architecture of a network application that +processes potentially hostile data from the Internet? (Hint: Focus on the fact that in Unix +you can give different privileges to processes.) + +\item Explain what are the differences between dictionary and brute forcing attacks against passwords. + +\end{enumerate} +\end{document} + +%%% Local Variables: +%%% mode: latex +%%% TeX-master: t +%%% End: