diff --git a/exam/ex.tex b/exam/ex.tex
index 195ee22..586c0e3 100644
--- a/exam/ex.tex
+++ b/exam/ex.tex
@@ -415,7 +415,9 @@
       signature is $\unit[78043.5]{bytes}$ big.
 
     \item The signature can be made smaller if the underlying graphs have less
-      vertices. The signature shrinks linearly with the number of vertices.
+      vertices. Unfortunately, this comes at a reduced level of security, which
+      means that the tradeoff between security and performance has to be
+      balanced carefully.
 
   \end{enumerate}