author | Christian Urban <christian dot urban at kcl dot ac dot uk> |
Tue, 26 Nov 2013 06:33:31 +0000 | |
changeset 139 | 059527f0615a |
parent 137 | 6fc7de0f23ba |
child 306 | c3ad0cf9db50 |
permissions | -rw-r--r-- |
74
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
1 |
\documentclass{article} |
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
2 |
\usepackage{charter} |
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
3 |
\usepackage{hyperref} |
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
4 |
\usepackage{amssymb} |
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
5 |
\usepackage{proof} |
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
6 |
|
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
7 |
\begin{document} |
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
8 |
|
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
9 |
\section*{Homework 7} |
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
10 |
|
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
11 |
\begin{enumerate} |
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
12 |
\item Suppose a judgement is of the form: |
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
13 |
\begin{center} |
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
14 |
$Alice\;\textit{says}\;S \wedge Bob\;\textit{says}\;S \vdash Bob\;\textit{says}\;S \wedge Alice\;\textit{says}\;S$ |
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
15 |
\end{center} |
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
16 |
|
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
17 |
Assume you want to use the inference rule |
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
18 |
|
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
19 |
\begin{center} |
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
20 |
\mbox{\infer{\Gamma \vdash F_1 \wedge F_2}{\Gamma \vdash F_1 & \Gamma \vdash F_2}} |
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
21 |
\end{center} |
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
22 |
|
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
23 |
for constructing a proof of the judgement. What do the premises look like? |
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
24 |
|
139
059527f0615a
added
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
137
diff
changeset
|
25 |
\item What are the benefits of using Logic to describe protocols and access control problems? |
059527f0615a
added
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
137
diff
changeset
|
26 |
|
059527f0615a
added
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
137
diff
changeset
|
27 |
|
137
6fc7de0f23ba
added HW 07
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
97
diff
changeset
|
28 |
%\item The informal meaning of the formula \mbox{$P\;\mapsto\;Q$} is `$P$ speaks for |
6fc7de0f23ba
added HW 07
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
97
diff
changeset
|
29 |
%$Q$'. Give a definition for this formula in terms of $\textit{says}$. |
74
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
30 |
|
137
6fc7de0f23ba
added HW 07
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
97
diff
changeset
|
31 |
%\item In Unix, what should be the general architecture of a network application that |
6fc7de0f23ba
added HW 07
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
97
diff
changeset
|
32 |
%processes potentially hostile data from the Internet? (Hint: Focus on the fact that in Unix |
6fc7de0f23ba
added HW 07
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
97
diff
changeset
|
33 |
%you can give different privileges to processes.) |
74
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
34 |
|
137
6fc7de0f23ba
added HW 07
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
97
diff
changeset
|
35 |
%\item Explain what are the differences between dictionary and brute forcing attacks against passwords. |
74
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
36 |
|
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
37 |
\end{enumerate} |
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
38 |
\end{document} |
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
39 |
|
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
40 |
%%% Local Variables: |
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
41 |
%%% mode: latex |
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
42 |
%%% TeX-master: t |
fb14a8e1b00d
added hw 7
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
43 |
%%% End: |