--- a/slides/slides05.tex	Tue Oct 21 12:37:18 2014 +0100
+++ b/slides/slides05.tex	Tue Oct 21 12:42:19 2014 +0100
@@ -477,18 +477,19 @@
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-\mode<presentation>{
 \begin{frame}[c]
 \frametitle{Best Practices}
 
-{\bf Principle 1:} Every message should say what it means: the interpretation of 
-a message should not depend on the context.\bigskip\pause
+{\bf Principle 1:} Every message should say what it means: the
+interpretation of a message should not depend on the
+context.\bigskip\pause
 
-{\bf Principle 2:} If the identity of a principal is essential to the meaning of a message, it is prudent 
-to mention the principal’s name explicitly in the message (though difficult).\bigskip
+{\bf Principle 2:} If the identity of a principal is essential
+to the meaning of a message, it is prudent to mention the
+principal’s name explicitly in the message (though
+difficult).\bigskip
 
-
-\end{frame}}
+\end{frame}
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -518,10 +519,16 @@
 \begin{frame}[c]
 \frametitle{Best Practices}
 
-{\bf Principle 4:} The protocol designer should know which trust relations his protocol depends on, and why the dependence is necessary. The reasons for particular trust relations being acceptable should be explicit though they will be founded on judgment and policy rather than on logic.\bigskip
+{\bf Principle 4:} The protocol designers should know which
+trust relations their protocol depends on, and why the
+dependence is necessary. The reasons for particular trust
+relations being acceptable should be explicit though they will
+be founded on judgment and policy rather than on
+logic.\bigskip
 
-
Example Certification Authorities: CAs are trusted to certify a key only after proper steps 
-have been taken to identify the principal that owns it.
+
Example Certification Authorities: CAs are trusted to certify
+a key only after proper steps have been taken to identify the
+principal that owns it.
 
 \end{frame}
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   
@@ -536,7 +543,7 @@
 \begin{quote}
 Formal methods can be an excellent way of finding 
 bugs in security protocol designs as they force the designer 
-to make everything explicit and thus confront dif$\!$ficult design 
+to make everything explicit and thus confront difficult design 
 choices that might otherwise be fudged. 
 \end{quote}