+\begin{frame}[fragile]
+ \frametitle{Public key authentication}
+ \begin{block}{\textasciitilde/.ssh/authorized\_keys}
+ \begin{lstlisting}
+option1="option1value",option2="option2value"...optionn="optionnvalue" ssh-rsa\
+AAAB4N.....
+ \end{lstlisting}
+ \end{block}
+\end{frame}
+