src/HOL/Auth/All_Symmetric.thy

+theory All_Symmetric
+imports Message
+begin
+
+text {* All keys are symmetric *}
+
+defs all_symmetric_def: "all_symmetric \<equiv> True"
+
+lemma isSym_keys: "K \<in> symKeys"
+  by (simp add: symKeys_def all_symmetric_def invKey_symmetric) 
+
+end