src/HOL/Auth/CertifiedEmail.thy
changeset 14200 d8598e24f8fa
parent 14145 2e31b8cc8788
child 14207 f20fbb141673
--- a/src/HOL/Auth/CertifiedEmail.thy	Tue Sep 23 15:40:27 2003 +0200
+++ b/src/HOL/Auth/CertifiedEmail.thy	Tue Sep 23 15:41:33 2003 +0200
@@ -93,14 +93,15 @@
 declare analz_into_parts [dest]
 
 (*A "possibility property": there are traces that reach the end*)
-lemma "\<exists>S2TTP. \<exists>evs \<in> certified_mail.
+lemma "[| Key K \<notin> used []; K \<in> symKeys |] ==> 
+       \<exists>S2TTP. \<exists>evs \<in> certified_mail.
            Says TTP S (Crypt (priSK TTP) S2TTP) \<in> set evs"
-apply (rule bexE [OF Key_supply1]) 
 apply (intro exI bexI)
 apply (rule_tac [2] certified_mail.Nil
                     [THEN certified_mail.CM1, THEN certified_mail.Reception,
                      THEN certified_mail.CM2, 
-                     THEN certified_mail.CM3], possibility, possibility, auto) 
+                     THEN certified_mail.CM3]) 
+apply (possibility, auto) 
 done