Add validation of recieved message and refactor code

Signed-off-by: Aleksandra Maciaga <aleksandra.maciaga@nokia.com>
Issue-ID: AAF-997
Change-Id: Idea7fba7cf33ff605c9f0980f82066b19559d29b
diff --git a/plans/aaf/certservice/docker-compose.yml b/plans/aaf/certservice/docker-compose.yml
index 83aff56..384158a 100644
--- a/plans/aaf/certservice/docker-compose.yml
+++ b/plans/aaf/certservice/docker-compose.yml
@@ -2,7 +2,7 @@
 
 services:
   ejbca:
-    image: primekey/ejbca-ce
+    image: primekey/ejbca-ce:6.15.2.5
     hostname: cahostname
     container_name: aafcert-ejbca
     ports: