--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/handouts/ho04.tex	Sat Oct 18 02:17:21 2014 +0100
@@ -0,0 +1,31 @@
+\documentclass{article}
+\usepackage{../style}
+\usepackage{../langs}
+\usetikzlibrary{patterns,decorations.pathreplacing}
+
+\begin{document}
+
+\section*{Handout 4 (Unix-Style Access Control)}
+
+Access control is essentially about deciding whether to grant
+access to a resource or deny it. This sounds easy. Right? Well
+it turns out that things are not as simple as seem at first.
+Let us study as a case how access is organised in Unix-like
+systems (Windows systems have generally similar access
+control, although the details might be quite different).
+ 
+Following the Unix-philosophy that everything is considered as
+a file, even memory or ports, access control is organised
+around 11 Bits that specify how a file can be accessed. There
+are three modes for access \textbf{r}ead, \textbf{w}rite and
+e\textbf{x}ecute. Moreover there are .... owner, group and
+everybody else.
+
+
+
+\end{document}
+
+%%% Local Variables: 
+%%% mode: latex
+%%% TeX-master: t
+%%% End: 

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/handouts/ho05.tex	Sat Oct 18 02:17:21 2014 +0100
@@ -0,0 +1,41 @@
+\documentclass{article}
+\usepackage{../style}
+\usepackage{../langs}
+\usetikzlibrary{patterns,decorations.pathreplacing}
+
+\begin{document}
+
+\section*{Handout 5 (Protocols)}
+
+The protocols we are interested here are generic descriptions
+of how to exchange messages in order to achieve a goal, be it
+establishing a mutual secure connection or being able to
+authenticate to a system. Our notion of protocol is
+deliberately quite general: it includes situations like the
+messages send between a key fob and a car in order to open
+doors or the messages that participants need to exchange in
+order to mine Bitcoins (which is often already called Bitcoin
+\emph{protocol}).
+
+Unlike the distant past where for example we had to meet a
+person in order to authenticate him or her (via a passport for
+example), the problem we are facing is that on the Internet we
+cannot easily be sure who we are ``talking'' to. The obvious
+reason is that only some electrons arrive at our computer; we
+do not see the person, or computer, behind the incoming
+electrons. Often there are is also no person behind the
+messages, rather than a computer system.
+
+
+
+Keyfobs - protocol
+
+attack such protocols because they use weak ciphers (Oyster
+card)
+
+\end{document}
+
+%%% Local Variables: 
+%%% mode: latex
+%%% TeX-master: t
+%%% End: