Updated security definitions

security_definitions.tex

@@ -88,7 +88,7 @@ A key note is that properties are checked not on the actual concrete model of th
 
 Before introducing the properties, we mention some basic predicates and conventions we use in their definition. The happy flow in SSH consists in a series of steps, the user first exchanges keys, then  requests for the authentication service, followed up by supplying valid credentials and authentication, concluded by opening of a channel. Whereas the first step is complex, the subsequent steps can be captured by the simple predicates {\dreqauth} , {\dauth} and {\dopchan} respectively. The predicates are defined in terms of the output generated at a given moment, with certain values of this output indicating that the step was performed successfully. For example, \textsc{ch\_open\_success} indicates that a channel has been opened successfully. Sometimes, we also need the input that generated the output, in order to distinguish this step from a different step. In particular, requesting the authentication service is distinguished from requesting the connection service by \textsc{sr\_auth}. 
 \begin{center}
-\begin{lstlisting}
+\begin{lstlisting}[basicstyle=\footnotesize]
 	hasReqAuth := inp=SR_AUTH & out=SR_ACCEPT
 	hasAuth := out=UA_PK_OK | out=UA_PW_OK
 	hasOpenedChannel := out=CH_OPEN_SUCCESS