diff --git a/exam/ex.tex b/exam/ex.tex
index d76a3c9..45bacfd 100644
--- a/exam/ex.tex
+++ b/exam/ex.tex
@@ -180,7 +180,8 @@
       (KEM). The underlying hard problem (arbitrary linear binary code decoding)
       is currently believed to be secure against quantum adversaries. 
 
-    \item \TODO
+    \item The authors introduce a post-quantum public-key cryptosystem based on
+      linear codes.
 
     \item IND-CCA2 is proven for both the KEM and the PKC. IND-CPA is proven for
       the KEM.