
diff -r be35ff24cccc -r d1d07f05325a slides08.tex
--- a/slides08.tex	Sun Dec 09 13:00:33 2012 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,747 +0,0 @@
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-
-% beamer stuff 
-\renewcommand{\slidecaption}{APP 08, King's College London, 20 November 2012}
-\newcommand{\dn}{\stackrel{\mbox{\scriptsize def}}{=}}% for definitions
-\newcommand{\bl}[1]{\textcolor{blue}{#1}}
-
-\begin{document}
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}<1>[t]
-\frametitle{%
-  \begin{tabular}{@ {}c@ {}}
-  \\
-  \LARGE Access Control and \\[-3mm] 
-  \LARGE Privacy Policies (8)\\[-6mm] 
-  \end{tabular}}\bigskip\bigskip\bigskip
-
-  %\begin{center}
-  %\includegraphics[scale=1.3]{pics/barrier.jpg}
-  %\end{center}
-
-\normalsize
-  \begin{center}
-  \begin{tabular}{ll}
-  Email:  & christian.urban at kcl.ac.uk\\
-  Of$\!$fice: & S1.27 (1st floor Strand Building)\\
-  Slides: & KEATS (also homework is there)\\
-  \end{tabular}
-  \end{center}
-
-
-\end{frame}}
- %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%     
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  \mode<presentation>{
-  \begin{frame}[c]
-  \frametitle{Last Week}
-
-Andrew Secure RPC Protocol:
-\bl{$A$} and \bl{$B$} share a key private \bl{$K_{AB}$} and want to identify
-each other\bigskip
-
- \begin{itemize}
- \item \bl{$A \,\text{sends}\, B :  A, N_A$} 
- \item \bl{$B\,\text{sends}\, A : \{N_A, K'_{AB}\}_{K_{AB}}$}
- \item \bl{$A \,\text{sends}\, B : \{N_A\}_{K'_{AB}}$}
- \end{itemize}
- 
-  \end{frame}}
-  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%    
-    
- %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  \mode<presentation>{
-  \begin{frame}[t]
-  \frametitle{Protocols}
- 
-\mbox{} 
-  
-\begin{tabular}{l}
-{\Large \bl{$A\;\text{sends}\; B : \ldots$}}\\
-\onslide<2->{\Large \bl{$B\;\text{sends}\; A : \ldots$}}\\
-\onslide<2->{\Large \;\;\;\;\;\bl{$:$}}\bigskip
-\end{tabular}  
-  
- \begin{itemize}
- \item by convention \bl{$A$}, \bl{$B$} are named principals \bl{Alice\ldots}\\
- but most likely they are programs, which just follow some instructions (they are more like roles)\bigskip
-\item<2-> indicates one ``protocol run'', or session,  which specifies some 
-order in the communication
-\item<2-> there can be several sessions in parallel (think of wifi routers) 
-\end{itemize} 
-  
-  \end{frame}}
-  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
-  
-   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  \mode<presentation>{
-  \begin{frame}[c]
-  \frametitle{Last Week}
-
-
-\bl{$A$} and \bl{$B$} share the key \bl{$K_{AB}$} and want to identify
-each other\bigskip
-
- \begin{itemize}
- \item \bl{$A \,\text{sends}\, B :  A, N_A$} 
- \item \bl{$B\,\text{sends}\, A : \{N_A, K'_{AB}\}_{K_{AB}}$}
- \item \bl{$A \,\text{sends}\, B : \{N_A\}_{K'_{AB}}$}
- \end{itemize}
-  \end{frame}}
-  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%      
-     
- %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  \mode<presentation>{
-  \begin{frame}[c]
-  \frametitle{Defeating Challenge-Response}
-
-\noindent
-A \alert{reflection attack}: an intruder \bl{$I$} impersonates \bl{$B$}.
-
-\begin{center}
-\begin{tabular}{@{\hspace{-7mm}}c@{\hspace{1mm}}c@{}}
-\begin{tabular}{@{}l@{}}
-\onslide<1->{\bl{$A \,\text{sends}\, I :  A, N_A$}}\\ 
-\onslide<4->{\bl{$I \,\text{sends}\, A :  \{N_A,\!K'_{\!AB}\}_{K_{\!AB}}$}}\\ 
-\onslide<5->{\bl{$A \,\text{sends}\, I : \{N_A\}_{K'_{AB}}$}}\\
-\end{tabular}
-&
-\begin{tabular}{@{}l@{}}
-\onslide<2->{\bl{$I \,\text{sends}\, A :  B, N_A$}}\\ 
-\onslide<3->{\bl{$A \,\text{sends}\, I :  \{N_A,\!K'_{\!AB}\}_{K_{\!AB}}$}}\\ 
-\onslide<6->{\bl{$I \,\text{sends}\, A : \{N_A\}_{K'_{AB}}$}}\\
-\end{tabular}
-\end{tabular}
-\end{center}\bigskip
-
-\onslide<7->{Sounds stupid: ``\ldots answering a question with a counter question''\medskip\\
-was originally developed at CMU for terminals to connect to 
-workstations (e.g., file servers)}
-
-  \end{frame}}
- %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%         
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}[c]
-\frametitle{Identify Friend or Foe}
-
-\begin{center}
-\onslide<3->{\mbox{}\hspace{3.4cm}\includegraphics[scale=0.55]{pics/MigInMiddle.jpg}}
-\end{center}
-
-\begin{textblock}{6}(0.3,2)
-\onslide<2->{
-198?: war between Angola (supported by Cuba)
-and Namibia (supported by SA)}
-\end{textblock}
-
-\begin{textblock}{3}(12.5,4.6)
-  \onslide<3->{
-  \begin{tikzpicture}
-  \node at (0,0) [single arrow, fill=red,text=white, rotate=-50, shape border rotate=180]{``bystander''};
-  \end{tikzpicture}}
-  \end{textblock}
-
-\begin{textblock}{3}(10.9,10)
-  \onslide<3->{
-  \begin{tikzpicture}
-  \node at (0,0) [single arrow, fill=red,text=white, rotate=-40, shape border rotate=180]{attacker};
-  \end{tikzpicture}}
-  \end{textblock}
-  
-\only<4->{
-\begin{textblock}{6}(0.3,9)
-being outsmarted by Angola/Cuba
-ended SA involvement (?)
-\end{textblock}}
-\only<5->{
-\begin{textblock}{6}(0.3,13)
-IFF opened up a nice side-channel attack
-\end{textblock}}
-\end{frame}}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
-
-  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-  \mode<presentation>{
-  \begin{frame}[c]
-  \frametitle{Encryption to the Rescue?}
-
-
- \begin{itemize}
- \item \bl{$A \,\text{sends}\, B :  \{A, N_A\}_{K_{AB}}$}\hspace{1cm} encrypted\bigskip 
- \item \bl{$B\,\text{sends}\, A : \{N_A, K'_{AB}\}_{K_{AB}}$}\bigskip
- \item \bl{$A \,\text{sends}\, B : \{N_A\}_{K'_{AB}}$}\bigskip
- \end{itemize}\pause
- 
-means you need to send separate ``Hello'' signals (bad), or worse 
-share a single key between many entities
-\end{frame}}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%      
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}[c]
-\frametitle{Protocol Attacks}
-
-\begin{itemize}
-\item replay attacks
-\item reflection attacks
-\item man-in-the-middle attacks
-\item timing attacks
-\item parallel session attacks
-\item binding attacks (public key protocols)
-\item changing environment / changing assumptions\bigskip
-
-\item (social engineering attacks)
-\end{itemize}
-\end{frame}}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
-  
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}[c]
-\frametitle{Replay Attacks}
-
-Schroeder-Needham protocol: exchange of a symmetric key with a trusted 3rd-party \bl{$S$}: 
-
-\begin{center}
-\begin{tabular}{r@ {\hspace{1mm}}l}
-\bl{$A \rightarrow S :$} & \bl{$A, B, N_A$}\\
-\bl{$S \rightarrow A :$} & \bl{$\{N_A, B, K_{AB},\{K_{AB}, A\}_{K_{BS}} \}_{K_{AS}}$}\\
-\bl{$A \rightarrow B :$} & \bl{$\{K_{AB}, A\}_{K_{BS}} $}\\
-\bl{$B \rightarrow A :$} & \bl{$\{N_B\}_{K_{AB}}$}\\
-\bl{$A \rightarrow B :$} & \bl{$\{N_B-1\}_{K_{AB}}$}\\
-\end{tabular}
-\end{center}\bigskip\pause
-
-at the end of the protocol both \bl{$A$} and \bl{$B$} should be in the possession of the secret key
-\bl{$K_{AB}$} and know that the other principal has the key
-
-\end{frame}}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
-
-  
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}[c]
-\frametitle{Nonces}
-
-\begin{enumerate}
-\item I generate a nonce (random number) and send it to you encrypted with a key we share
-\item you increase it by one, encrypt it under a key I know and send
-it back to me
-\end{enumerate}
-
-
-I can infer:
-
-\begin{itemize}
-\item you must have received my message
-\item you could only have generated your answer after I send you my initial
-message
-\item if only you and me know the key, the message must have come from you
-\end{itemize}
-
-\end{frame}}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}[c]
-
-\begin{center}
-\begin{tabular}{l}
-\bl{$A \rightarrow S :$} \bl{$A, B, N_A$}\\
-\bl{$S \rightarrow A :$} \bl{$\{N_A, B, K_{AB},\{K_{AB}, A\}_{K_{BS}} \}_{K_{AS}}$}\\
-\bl{$A \rightarrow B :$} \bl{$\{K_{AB}, A\}_{K_{BS}} $}\\
-\bl{$B \rightarrow A :$} \bl{$\{N_B\}_{K_{AB}}$}\\
-\bl{$A \rightarrow B :$} \bl{$\{N_B-1\}_{K_{AB}}$}\pause\\
-\hspace{5cm}compromise \bl{$K_{AB}$}\pause\\
-\bl{$A \rightarrow S :$} \bl{$A, B, N'_A$}\\
-\bl{$S \rightarrow A :$} \bl{$\{N'_A, B, K'_{AB},\{K'_{AB}, A\}_{K_{BS}} \}_{K_{AS}}$}\pause\\
-\bl{$I(A) \rightarrow B :$} \bl{$\{K_{AB}, A\}_{K_{BS}} $}\hspace{0.5cm} replay of older run\pause\\
-\bl{$B \rightarrow I(A) :$} \bl{$\{N'_B\}_{K_{AB}}$}\\
-\bl{$I(A) \rightarrow B :$} \bl{$\{N'_B-1\}_{K_{AB}}$}\
-\end{tabular}
-\end{center}\pause
-
-\bl{$B$} believes it is following the correct protocol,
-intruder \bl{$I$} can form the correct response because it knows \bl{$K_{AB}$} and
-talks to \bl{$B$} masquerading as \bl{$A$}
-\end{frame}}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}[c]
-
-\begin{center}
-\includegraphics[scale=0.5]{pics/dogs.jpg}
-\end{center}
-
-\end{frame}}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
-
-
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}[c]
-\frametitle{Replay Attacks}
-
-Andrew Secure RPC protocol: exchanging a new key
-between \bl{$A$} and \bl{$B$}
-
-\begin{center}
-\begin{tabular}{l}
-\bl{$A \rightarrow B :$} \bl{$A, \{N_A\}_{K_{AB}}$}\\
-\bl{$B \rightarrow A :$} \bl{$\{N_A+1, N_B\}_{K_{AB}}$}\\
-\bl{$A \rightarrow B :$} \bl{$\{N_B+1\}_{K_{AB}}$}\\
-\bl{$B \rightarrow A :$} \bl{$\{K^{new}_{AB}, N^{new}_B\}_{K_{AB}}$}\\
-\end{tabular}
-\end{center}\bigskip\pause
-
-Assume nonces are represented as bit-sequences of the same length as keys
-\begin{center}
-\begin{tabular}{@{}l@{}}
-\bl{$A \rightarrow B :$} \bl{$A, \{N_A\}_{K_{AB}}$}\\
-\bl{$B \rightarrow A :$} \bl{$\{N_A+1, N_B\}_{K_{AB}}$}\\
-\bl{$A \rightarrow I(B) :$} \bl{$\{N_B+1\}_{K_{AB}}$}\hspace{0.5mm}intercepts\\
-\bl{$I(B) \rightarrow A :$} \bl{$\{N_A+1, N_B\}_{K_{AB}}$}\hspace{0.5mm}resend 2nd msg\\
-\end{tabular}
-\end{center}
-\end{frame}}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}[c]
-\frametitle{Time-Stamps}
-
-The Schroeder-Needham protocol can be fixed by including a time-stamp (e.g., in Kerberos):
-
-\begin{center}
-\begin{tabular}{r@ {\hspace{1mm}}l}
-\bl{$A \rightarrow S :$} & \bl{$A, B, N_A$}\\
-\bl{$S \rightarrow A :$} & \bl{$\{N_A, B, K_{AB},\{K_{AB}, A, T_S\}_{K_{BS}} \}_{K_{AS}}$}\\
-\bl{$A \rightarrow B :$} & \bl{$\{K_{AB}, A, T_S\}_{K_{BS}} $}\\
-\bl{$B \rightarrow A :$} & \bl{$\{N_B\}_{K_{AB}}$}\\
-\bl{$A \rightarrow B :$} & \bl{$\{N_B-1\}_{K_{AB}}$}\\
-\end{tabular}
-\end{center}\bigskip\pause
-
-but nothing is for free: then you need to synchronise time and possibly become a victim to
-timing attacks
-
-\end{frame}}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}[c]
-
-It can also be fixed by including another nonce:
-
-\begin{center}
-\begin{tabular}{r@ {\hspace{1mm}}l}
-\bl{$A \rightarrow B :$} & \bl{$A$}\\
-\bl{$B \rightarrow A :$} & \bl{$\{A, N_B\}_{K_{BS}}$}\\
-\bl{$A \rightarrow S :$} & \bl{$A, B, N_A, \{A, N_B\}_{K_{BS}}$}\\
-\bl{$S \rightarrow A :$} & \bl{$\{N_A, B, K_{AB},\{K_{AB}, A, N_B\}_{K_{BS}} \}_{K_{AS}}$}\\
-\bl{$A \rightarrow B :$} & \bl{$\{K_{AB}, A, N_B\}_{K_{BS}} $}\\
-\bl{$B \rightarrow A :$} & \bl{$\{N_B\}_{K_{AB}}$}\\
-\bl{$A \rightarrow B :$} & \bl{$\{N_B-1\}_{K_{AB}}$}\\
-\end{tabular}
-\end{center}\bigskip\pause
-
-but nothing is for free: then you need to synchronise time and possibly become victim to
-timing attacks
-
-\end{frame}}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
-
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}[c]
-\frametitle{Binding Attacks}
-
-with public-private keys it is important that the public key is \alert{bound} 
-to the right owner (verified by a certification authority \bl{$CA$})
-
-\begin{center}
-\begin{tabular}{l}
-\bl{$A \rightarrow CA :$} \bl{$A, B, N_A$}\\
-\bl{$CA \rightarrow A :$} \bl{$CA, \{CA, A, N_A, K^{pub}_{B}\}_{K^{pub}_{A}}$}\\
-\end{tabular}
-\end{center}\bigskip
-
-\bl{$A$} knows \bl{$K^{priv}_A$} and can verify the message came from \bl{$CA$}
-in response to \bl{$A$}'s message and trusts \bl{$K^{pub}_{B}$} is \bl{$B$}'s public key
-
-
-\end{frame}}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
-
-
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}[c]
-\frametitle{Binding Attacks}
-
-\begin{center}
-\begin{tabular}{l}
-\bl{$A \rightarrow I(CA) :$} \bl{$A, B, N_A$}\\
-\bl{$I(A) \rightarrow CA :$} \bl{$A, I, N_A$}\\
-\bl{$CA \rightarrow I(A) :$} \bl{$CA, \{CA, A, N_A, K^{pub}_{I}\}_{K^{pub}_{A}}$}\\
-\bl{$I(CA) \rightarrow A :$} \bl{$CA, \{CA, A, N_A, K^{pub}_{I}\}_{K^{pub}_{A}}$}\\
-\end{tabular}
-\end{center}\pause
-
-\bl{$A$} now encrypts messages for \bl{$B$} with the public key of \bl{$I$}
-(which happily decrypts them with its private key)
-
-\end{frame}}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
-
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}[c]
-
-There are plenty of other protocols and attacks. This could go on ``forever''.\pause\bigskip
-
-We look here on one more kind of attacks that are because of a changing environment.
-
-\end{frame}}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}[t]
-\frametitle{Changing Environment Attacks}
-
-\begin{itemize}
-\item all protocols rely on some assumptions about the environment
-(e.g., cryptographic keys cannot be broken)\bigskip\pause
-\end{itemize}
-
-\only<2>{
-\begin{itemize}
-\item in the ``good olden days'' (1960/70) rail transport was cheap, so fraud was not
-worthwhile
-\end{itemize}}
-
-\only<3>{
-\begin{itemize}
-\item when it got expensive, some people bought cheaper monthly tickets for a suburban 
-station and a nearby one, and one for the destination and a nearby one
-\item a large investment later all barriers were automatic and tickets could record state
-\end{itemize}}
-
-\only<4>{
-\begin{itemize}
-\item but suddenly the environment changed: rail transport got privatised creating many 
-competing companies
-potentially cheating each other
-\item revenue from monthly tickets was distributed according to a formula involving where the ticket was bought\ldots
-\end{itemize}}
-
-\only<5>{
-\begin{itemize}
-\item apart from bad outsiders (passengers), you also had bad insiders (rail companies)
-\item chaos and litigation ensued
-\end{itemize}}
-
-\end{frame}}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}[c]
-
-A Man-in-the-middle attack in real life:
-
-\begin{itemize}
-\item the card only says yes or no to the terminal if the PIN is correct
-\item trick the card in thinking transaction is verified by signature
-\item trick the terminal in thinking the transaction was verified by PIN
-\end{itemize}
-
-\begin{minipage}{1.1\textwidth}
-\begin{center}
-\mbox{}\hspace{-6mm}\includegraphics[scale=0.5]{pics/chip-attack.png}
-\includegraphics[scale=0.3]{pics/chipnpinflaw.png}
-\end{center}
-\end{minipage}
-
-\end{frame}}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}[c]
-\frametitle{Problems with EMV}
-
-\begin{itemize}
-\item it is a wrapper for many protocols
-\item specification by consensus (resulted unmanageable complexity)
-\item its specification is 700 pages in English plus 2000+ pages for testing, additionally some 
-further parts are secret
-\item other attacks have been found
-
-\item one solution might be to require always online verification of the PIN with the bank
-\end{itemize}
-
-\end{frame}}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
-
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}[c]
-\frametitle{Problems with WEP (Wifi)}
-
-\begin{itemize}
-\item a standard ratified in 1999
-\item the protocol was designed by a committee not including cryptographers
-\item it used the RC4 encryption algorithm which is a stream cipher requiring a unique nonce
-\item WEP did not allocate enough bits for the nonce
-\item for authenticating packets it used CRC checksum which can be easily broken
-\item the network password was used to directly encrypt packages (instead of a key negotiation protocol)\bigskip
-\item encryption was turned of by default
-\end{itemize}
-
-\end{frame}}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
-
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}[c]
-\frametitle{Protocols are Difficult}
-
-\begin{itemize}
-\item even the systems designed by experts regularly fail\medskip
-\item try to make everything explicit (you need to authenticate all data you might rely on)\medskip
-\item the one who can fix a system should also be liable for the losses\medskip
-\item cryptography is often not {\bf the} answer\bigskip\bigskip  
-\end{itemize}
-
-logic is one way protocols are studied in academia
-(you can use computers to search for attacks)
-
-\end{frame}}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
-
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}[c]
-\frametitle{Public-Key Infrastructure}
-
-\begin{itemize}
-\item the idea is to have a certificate authority (CA)
-\item you go to the CA to identify yourself
-\item CA: ``I, the CA, have verified that public key \bl{$P^{pub}_{Bob}$} belongs to Bob''\bigskip
-\item CA must be trusted by everybody
-\item What happens if CA issues a false certificate? Who pays in case of loss? (VeriSign 
-explicitly limits liability to \$100.)
-\end{itemize}
-
-\end{frame}}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
-
-
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}[c]
-\frametitle{Privacy, Anonymity et al}
-
-Some terminology:
-
-\begin{itemize}
-\item \alert{secrecy} is the mechanism used to limit the number of 
-principals with access to information (eg, cryptography or access controls)
-
-\item \alert{confidentiality} is the obligation to protect the secrets of other people 
-or organizations (secrecy for the benefit of an organisation)
-
-\item \alert{anonymity} is the ability to leave no evidence of an activity (eg, sharing a secret)
-
-\item \alert{privacy} is the ability or right to protect your personal secrets 
-(secrecy for the benefit of an individual)
-
-\end{itemize}
-
-\end{frame}}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}[t]
-\frametitle{Privacy vs Anonymity}
-
-\begin{itemize}
-\item everybody agrees that anonymity has its uses (e.g., voting, whistleblowers, peer-review)
-\end{itemize}\bigskip\bigskip\pause
-
-
-But privacy?\bigskip\bigskip
-
-``You have zero privacy anyway. Get over it.''\\
-\hfill{}Scott Mcnealy (CEO of Sun)\bigskip\\
-
-
-If you have nothing to hide, you have nothing to fear.
-
-\end{frame}}
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-\mode<presentation>{
-\begin{frame}[t]
-\frametitle{Privacy}
-
-private data can be often used against me
-
-\begin{itemize}
-\item if my location data becomes public, thieves will switch off their phones and help themselves in my home
-\item if supermarkets can build a profile of what I buy, they can use it to their advantage (banks - mortgages)
-\item my employer might not like my opinions\bigskip\pause
-
-\item one the other hand, Freedom-of-Information Act 
-\item medical data should be private, but medical research needs data
-\end{itemize}
-
-\end{frame}}
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-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
-\begin{frame}[t]
-\frametitle{Privacy Problems}
-
-\begin{itemize}
-\item Apple takes note of every dictation (send over the Internet to Apple)
-\item markets often only work, if data is restricted (to build trust)
-\item Social network can reveal data about you 
-\item have you tried the collusion extension for FireFox?
-\item I do use Dropbox, store cards\bigskip
-\item next week: anonymising data
-\end{itemize}
-
-\begin{textblock}{5}(12,8.9)
-\includegraphics[scale=0.3]{pics/gattaca.jpg}\\
-\small Gattaca (1997)
-\end{textblock}
-
-\end{frame}}
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
-
-
-\end{document}
-
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-%%% TeX-master: t
-%%% End: 
-




