Slides 2.3: Add a TODO for sealed sender (and a reading)

slides/2-3.tex

@@ -1589,6 +1589,18 @@
 	\end{columns}
 \end{frame}
 
+\begin{frame}{TODO: Sealed Sender}
+	\begin{columns}[c]
+		\begin{column}{1\textwidth}
+			\begin{itemize}
+				\item TODO:
+				\item Sealed sender
+				\item Analysis from 2021\footnote{\url{https://appliedcryptography.page/papers/\#sealed-sender}}
+			\end{itemize}
+		\end{column}
+	\end{columns}
+\end{frame}
+
 \begin{frame}{Can your message truly be secure after a hack?}
 	\begin{columns}[c]
 		\begin{column}{1\textwidth}