Add solution for 4h

exam/ex.tex

@@ -213,7 +213,15 @@
       message to obtain the symmetric key which can be used for further
       communication.
 
-    \item \TODO
+    \item The lowest security level treated by the authors is level 1 of the
+      NIST security levels corresponding to AES-128. The parameters depend on
+      whether the scheme is used for ephemeral or long-term keys and what kind
+      of code rate ($n_0$) is needed. For ephemeral keys with $n_0=2$ the
+      authors suggest values of: $p=14,939$, $t=136$, $d_v=11$ and $m=[4,3]$.
+      For long-term keys the authors suggest values of: $p=35,899$, $t=136$,
+      $d_v=9$, $m=[5,4]$, $\overline{t}=4$ and $b_0=44$. These parameters are
+      chosen with respect to an adversary using Information Set Decoding (ISD)
+      to find a solution to the underlying hard problem.
 
     \item \TODO