| author | Christian Urban <christian dot urban at kcl dot ac dot uk> |
| Tue, 21 Oct 2014 02:35:06 +0100 | |
| changeset 252 | fa151c0a3cf4 |
| parent 239 | 0db764174afb |
| child 276 | d7109c6e721d |
| permissions | -rw-r--r-- |
|
97
efcac3016613
added hws
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
1 |
\documentclass{article}
|
|
efcac3016613
added hws
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
2 |
\usepackage{charter}
|
|
efcac3016613
added hws
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
3 |
\usepackage{hyperref}
|
|
efcac3016613
added hws
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
4 |
\usepackage{amssymb}
|
|
efcac3016613
added hws
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
5 |
|
|
efcac3016613
added hws
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
6 |
\begin{document}
|
|
efcac3016613
added hws
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
7 |
|
|
efcac3016613
added hws
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
8 |
\section*{Homework 5}
|
|
efcac3016613
added hws
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
9 |
|
|
efcac3016613
added hws
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
10 |
\begin{enumerate}
|
|
239
0db764174afb
updated home works
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
155
diff
changeset
|
11 |
\item Consider the following simple mutual authentication protocol: |
|
0db764174afb
updated home works
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
155
diff
changeset
|
12 |
|
|
0db764174afb
updated home works
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
155
diff
changeset
|
13 |
\begin{center}
|
|
0db764174afb
updated home works
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
155
diff
changeset
|
14 |
\begin{tabular}{ll}
|
|
0db764174afb
updated home works
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
155
diff
changeset
|
15 |
$A \rightarrow B$: & $N_a$\\ |
|
0db764174afb
updated home works
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
155
diff
changeset
|
16 |
$B \rightarrow A$: & $\{N_a, N_b\}_{K_{ab}}$\\
|
|
0db764174afb
updated home works
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
155
diff
changeset
|
17 |
$A \rightarrow B$: & $N_b$\\ |
|
0db764174afb
updated home works
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
155
diff
changeset
|
18 |
\end{tabular}
|
|
0db764174afb
updated home works
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
155
diff
changeset
|
19 |
\end{center}
|
|
0db764174afb
updated home works
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
155
diff
changeset
|
20 |
|
|
0db764174afb
updated home works
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
155
diff
changeset
|
21 |
Explain how an attacker $B'$ can launch an impersonation attack by |
|
0db764174afb
updated home works
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
155
diff
changeset
|
22 |
intercepting all messages for $B$ and make $A$ decrypt her own challenges. |
|
0db764174afb
updated home works
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
155
diff
changeset
|
23 |
|
|
0db764174afb
updated home works
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
155
diff
changeset
|
24 |
|
|
252
fa151c0a3cf4
updated slides
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
239
diff
changeset
|
25 |
\item Before starting a TCP connection, client and servers |
|
fa151c0a3cf4
updated slides
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
239
diff
changeset
|
26 |
perform a three-way handshake: |
|
97
efcac3016613
added hws
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
27 |
|
|
efcac3016613
added hws
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
28 |
\begin{center}
|
|
252
fa151c0a3cf4
updated slides
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
239
diff
changeset
|
29 |
\begin{tabular}{rl}
|
|
fa151c0a3cf4
updated slides
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
239
diff
changeset
|
30 |
$A \rightarrow S$: & SYN\\ |
|
fa151c0a3cf4
updated slides
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
239
diff
changeset
|
31 |
$S \rightarrow A$: & SYN-ACK\\ |
|
fa151c0a3cf4
updated slides
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
239
diff
changeset
|
32 |
$A \rightarrow S$: & ACK\\ |
|
97
efcac3016613
added hws
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
33 |
\end{tabular}
|
|
efcac3016613
added hws
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
34 |
\end{center}
|
|
efcac3016613
added hws
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
35 |
|
|
252
fa151c0a3cf4
updated slides
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
239
diff
changeset
|
36 |
How can this protocol be abused causing trouble on the server? |
|
97
efcac3016613
added hws
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
37 |
|
|
efcac3016613
added hws
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
38 |
\end{enumerate}
|
|
efcac3016613
added hws
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
39 |
\end{document}
|
|
efcac3016613
added hws
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
40 |
|
|
efcac3016613
added hws
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
41 |
%%% Local Variables: |
|
efcac3016613
added hws
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
42 |
%%% mode: latex |
|
efcac3016613
added hws
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
43 |
%%% TeX-master: t |
|
efcac3016613
added hws
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
44 |
%%% End: |