diff --git a/ChangeLog b/ChangeLog
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,15 @@
+2019-11-12  John D. Ramsdell  <ramsdell@mitre.org>
+
+	* cpsa.cabal (Version): Tagged as 3.6.5
+
+	* src/CPSA/Lib/Strand.hs (tryPermProb): Rewrote tryPermProb so
+	that it uses tryPerm.
+
+2019-11-08  John D. Ramsdell  <ramsdell@mitre.org>
+
+	* src/CPSA/Lib/Strand.hs (tryPermProb):  Added missing invperm to
+	the third line of tryPermProb, and reenabled multistrand thinning.
+
 2019-10-21  John D. Ramsdell  <ramsdell@gootoo.mitre.org>
 
 	* cpsa.cabal (Version): Tagged as 3.6.4
diff --git a/NEWS b/NEWS
--- a/NEWS
+++ b/NEWS
@@ -1,5 +1,10 @@
 CPSA NEWS
 
+  November 2019:
+
+* Release 3.6.5 is a bug fix release.  There are no user visible
+  changes.
+
   October 2019:
 
 * Release 3.6.4 adds support for the latest version of the GHC
diff --git a/cpsa.cabal b/cpsa.cabal
--- a/cpsa.cabal
+++ b/cpsa.cabal
@@ -1,5 +1,5 @@
 Name:                   cpsa
-Version:                3.6.4
+Version:                3.6.5
 Maintainer:             mliskov@mitre.org
 Cabal-Version:          >= 1.6
 License:                BSD3
diff --git a/src/CPSA/Lib/Strand.hs b/src/CPSA/Lib/Strand.hs
--- a/src/CPSA/Lib/Strand.hs
+++ b/src/CPSA/Lib/Strand.hs
@@ -884,13 +884,8 @@
 tryPermProb :: Algebra t p g s e c => Gist t g ->
            Gist t g -> [Sid] -> [Sid] -> ((g, e), (g, e), [Sid]) -> Bool
 tryPermProb g g' prob prob' (fenv, renv, perm) =
-    checkOrigs g g' fenv perm &&
-    checkOrigs g' g renv perm &&
-    checkFacts g g' fenv perm &&
-    checkFacts g' g renv (invperm perm) &&
-    containsMapped (permutePair perm) (gorderings g') (gorderings g) &&
-    containsMapped (permutePair perm) (gleadsto g') (gleadsto g) &&
-    all (\n -> perm !! (prob !! n) == prob' !! n) [0..((length prob)-1)]
+    all (\n -> perm !! (prob !! n) == prob' !! n) [0..((length prob)-1)] &&
+    tryPerm g g' (fenv, renv, perm)
 
 invperm :: [Int] -> [Int]
 invperm p = map snd (L.sortOn fst (zip p [0..]))
diff --git a/tst/aik.tst b/tst/aik.tst
--- a/tst/aik.tst
+++ b/tst/aik.tst
@@ -1,6 +1,6 @@
 (herald "Anonymous identity protocol from TCG")
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from aik.scm")
 
 (defprotocol aikprot basic
diff --git a/tst/attest.tst b/tst/attest.tst
--- a/tst/attest.tst
+++ b/tst/attest.tst
@@ -1,6 +1,6 @@
 (herald attest-door)
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from attest.scm")
 
 (defprotocol attest-door basic
diff --git a/tst/axiom2.tst b/tst/axiom2.tst
--- a/tst/axiom2.tst
+++ b/tst/axiom2.tst
@@ -1,6 +1,6 @@
 (herald "Axiom 2 Protocol" (bound 20))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from axiom2.scm")
 (comment "Strand count bounded at 20")
 
diff --git a/tst/blanchet.tst b/tst/blanchet.tst
--- a/tst/blanchet.tst
+++ b/tst/blanchet.tst
@@ -1,7 +1,7 @@
 (herald "Blanchet's Simple Example Protocol"
   (comment "There is a flaw in this protocol by design"))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from blanchet.scm")
 
 (defprotocol blanchet basic
diff --git a/tst/bltk_test.tst b/tst/bltk_test.tst
--- a/tst/bltk_test.tst
+++ b/tst/bltk_test.tst
@@ -1,6 +1,6 @@
 (herald "bltk Test File" (algebra diffie-hellman) (bound 12))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from bltk_test.scm")
 
 (defprotocol test diffie-hellman
diff --git a/tst/comp_test.tst b/tst/comp_test.tst
--- a/tst/comp_test.tst
+++ b/tst/comp_test.tst
@@ -1,6 +1,6 @@
 (herald "Main Example")
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from comp_test.scm")
 
 (defprotocol main-ex-src basic
diff --git a/tst/dh-ca.tst b/tst/dh-ca.tst
--- a/tst/dh-ca.tst
+++ b/tst/dh-ca.tst
@@ -1,6 +1,6 @@
 (herald dhca (algebra diffie-hellman))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from dh-ca.scm")
 
 (defprotocol dhca diffie-hellman
diff --git a/tst/dh_mim.tst b/tst/dh_mim.tst
--- a/tst/dh_mim.tst
+++ b/tst/dh_mim.tst
@@ -1,7 +1,7 @@
 (herald "Diffie-Hellman protocol, man-in-the-middle attack"
   (algebra diffie-hellman))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from dh_mim.scm")
 
 (defprotocol dh_mim diffie-hellman
diff --git a/tst/dh_mim2.tst b/tst/dh_mim2.tst
--- a/tst/dh_mim2.tst
+++ b/tst/dh_mim2.tst
@@ -1,7 +1,7 @@
 (herald "Diffie-Hellman protocol, man-in-the-middle attack"
   (algebra diffie-hellman))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from dh_mim2.scm")
 
 (defprotocol dh_mim diffie-hellman
diff --git a/tst/dh_sig.tst b/tst/dh_sig.tst
--- a/tst/dh_sig.tst
+++ b/tst/dh_sig.tst
@@ -1,6 +1,6 @@
 (herald "Signed DH exchange" (algebra diffie-hellman))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from dh_sig.scm")
 
 (defprotocol dh_sig diffie-hellman
diff --git a/tst/dh_test.tst b/tst/dh_test.tst
--- a/tst/dh_test.tst
+++ b/tst/dh_test.tst
@@ -1,7 +1,7 @@
 (herald "Diffie-Hellman protocol, man-in-the-middle attack"
   (algebra diffie-hellman) (bound 20))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from dh_test.scm")
 (comment "Strand count bounded at 20")
 
diff --git a/tst/dhnsl_basic.tst b/tst/dhnsl_basic.tst
--- a/tst/dhnsl_basic.tst
+++ b/tst/dhnsl_basic.tst
@@ -1,7 +1,7 @@
 (herald "Diffie-Hellman enhanced Needham-Schroeder-Lowe Protocol"
   (algebra diffie-hellman))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from dhnsl_basic.scm")
 
 (defprotocol dhnsl diffie-hellman
diff --git a/tst/dhnsl_use.tst b/tst/dhnsl_use.tst
--- a/tst/dhnsl_use.tst
+++ b/tst/dhnsl_use.tst
@@ -1,7 +1,7 @@
 (herald "Diffie-Hellman enhanced Needham-Schroeder-Lowe Protocol"
   (algebra diffie-hellman))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from dhnsl_use.scm")
 
 (defprotocol dhnsl diffie-hellman
diff --git a/tst/enrich.tst b/tst/enrich.tst
--- a/tst/enrich.tst
+++ b/tst/enrich.tst
@@ -1,6 +1,6 @@
 (herald enrich)
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from enrich.scm")
 
 (defprotocol enrich basic
diff --git a/tst/envelope.tst b/tst/envelope.tst
--- a/tst/envelope.tst
+++ b/tst/envelope.tst
@@ -1,6 +1,6 @@
 (herald "Envelope Protocol" (bound 20))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from envelope.scm")
 (comment "Strand count bounded at 20")
 
diff --git a/tst/ffgg.tst b/tst/ffgg.tst
--- a/tst/ffgg.tst
+++ b/tst/ffgg.tst
@@ -1,7 +1,7 @@
 (herald "The ffgg Protocol"
   (comment "From A Necessarily Parallel Attack by Jon K. Millen"))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from ffgg.scm")
 
 (defprotocol ffgg basic
diff --git a/tst/fluffy_draft03_gske.tst b/tst/fluffy_draft03_gske.tst
--- a/tst/fluffy_draft03_gske.tst
+++ b/tst/fluffy_draft03_gske.tst
@@ -3,7 +3,7 @@
   (comment
     "Based on the Internet-Draft: https://www.ietf.org/archive/id/draft-hardjono-ace-fluffy-03.txt"))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from fluffy_draft03_gske.scm")
 
 (defprotocol fluffy basic
diff --git a/tst/fnof_or.tst b/tst/fnof_or.tst
--- a/tst/fnof_or.tst
+++ b/tst/fnof_or.tst
@@ -2,7 +2,7 @@
   (comment
     "Version using variables of sort mesg, with ltk function emulated."))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from fnof_or.scm")
 
 (defprotocol or basic
diff --git a/tst/fnof_test.tst b/tst/fnof_test.tst
--- a/tst/fnof_test.tst
+++ b/tst/fnof_test.tst
@@ -1,7 +1,7 @@
 (herald "Function constraint test protocol"
   (comment "Skeletons 2, 4, and 7 should have no shapes."))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from fnof_test.scm")
 
 (defprotocol fnoftest basic
diff --git a/tst/fnof_woolam.tst b/tst/fnof_woolam.tst
--- a/tst/fnof_woolam.tst
+++ b/tst/fnof_woolam.tst
@@ -1,6 +1,6 @@
 (herald "Woo-Lam Protocol, using fnof to emulate ltk function")
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from fnof_woolam.scm")
 
 (defprotocol woolam basic
diff --git a/tst/fnof_yahalom.tst b/tst/fnof_yahalom.tst
--- a/tst/fnof_yahalom.tst
+++ b/tst/fnof_yahalom.tst
@@ -2,7 +2,7 @@
   "Yahalom Protocol with Forwarding Removed, using fnof to emulate ltk function"
   (bound 12))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from fnof_yahalom.scm")
 
 (defprotocol yahalom basic
diff --git a/tst/goals.tst b/tst/goals.tst
--- a/tst/goals.tst
+++ b/tst/goals.tst
@@ -1,6 +1,6 @@
 (herald goals)
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from goals.scm")
 
 (defprotocol ns basic
diff --git a/tst/iadh_um.tst b/tst/iadh_um.tst
# file too large to diff: tst/iadh_um.tst
diff --git a/tst/injection.tst b/tst/injection.tst
--- a/tst/injection.tst
+++ b/tst/injection.tst
@@ -2,7 +2,7 @@
   (comment "This protocol contains a man-in-the-middle"
     "attack discovered by Galvin Lowe."))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from injection.scm")
 
 (defprotocol ns diffie-hellman
diff --git a/tst/kerb.tst b/tst/kerb.tst
--- a/tst/kerb.tst
+++ b/tst/kerb.tst
@@ -1,4 +1,4 @@
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from kerb.scm")
 
 (defprotocol kerb-flawed basic
diff --git a/tst/kerberos++.tst b/tst/kerberos++.tst
--- a/tst/kerberos++.tst
+++ b/tst/kerberos++.tst
@@ -1,4 +1,4 @@
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from kerberos++.scm")
 
 (defprotocol kerberos basic
diff --git a/tst/lt_test.tst b/tst/lt_test.tst
--- a/tst/lt_test.tst
+++ b/tst/lt_test.tst
@@ -2,7 +2,7 @@
   (comment "First and third skeletons should have a shape,"
     "second and fourth should be dead."))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from lt_test.scm")
 
 (defprotocol lttest basic
diff --git a/tst/neq_test.tst b/tst/neq_test.tst
--- a/tst/neq_test.tst
+++ b/tst/neq_test.tst
@@ -2,7 +2,7 @@
   (comment "First skeleton should have a shape,"
     "second, and hird should be dead."))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from neq_test.scm")
 
 (defprotocol neqtest basic
diff --git a/tst/ns.tst b/tst/ns.tst
--- a/tst/ns.tst
+++ b/tst/ns.tst
@@ -2,7 +2,7 @@
   (comment "This protocol contains a man-in-the-middle"
     "attack discovered by Galvin Lowe."))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from ns.scm")
 
 (defprotocol ns basic
diff --git a/tst/or.tst b/tst/or.tst
--- a/tst/or.tst
+++ b/tst/or.tst
@@ -1,7 +1,7 @@
 (herald "Otway-Rees Protocol"
   (comment "Standard version using variables of sort mesg"))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from or.scm")
 
 (defprotocol or basic
diff --git a/tst/ordered.tst b/tst/ordered.tst
--- a/tst/ordered.tst
+++ b/tst/ordered.tst
@@ -1,6 +1,6 @@
 (herald ordered)
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from ordered.scm")
 
 (defprotocol ordered basic
diff --git a/tst/owang.tst b/tst/owang.tst
--- a/tst/owang.tst
+++ b/tst/owang.tst
@@ -1,4 +1,4 @@
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from owang.scm")
 
 (defprotocol wang basic
diff --git a/tst/owat.tst b/tst/owat.tst
--- a/tst/owat.tst
+++ b/tst/owat.tst
@@ -1,7 +1,7 @@
 (herald "One-way Authentication Test with bltk keys"
   (algebra diffie-hellman) (bound 12))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from owat.scm")
 
 (defprotocol owa diffie-hellman
diff --git a/tst/pkinit.tst b/tst/pkinit.tst
--- a/tst/pkinit.tst
+++ b/tst/pkinit.tst
@@ -1,6 +1,6 @@
 (herald "Kerberos PKINIT")
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from pkinit.scm")
 
 (defprotocol pkinit-flawed basic
diff --git a/tst/plaindh.tst b/tst/plaindh.tst
--- a/tst/plaindh.tst
+++ b/tst/plaindh.tst
@@ -1,7 +1,7 @@
 (herald "Plain diffie-hellman protocol with challenge-response"
   (algebra diffie-hellman))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from plaindh.scm")
 
 (defprotocol plaindh diffie-hellman
diff --git a/tst/priority_test.tst b/tst/priority_test.tst
--- a/tst/priority_test.tst
+++ b/tst/priority_test.tst
@@ -1,6 +1,6 @@
 (herald "Receive priority test protocol")
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from priority_test.scm")
 
 (defprotocol priority_test basic
diff --git a/tst/prottrans.tst b/tst/prottrans.tst
--- a/tst/prottrans.tst
+++ b/tst/prottrans.tst
@@ -1,6 +1,6 @@
 (herald "Protocol Transformations With Rules")
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from prottrans.scm")
 
 (defprotocol ns basic
diff --git a/tst/reflect.tst b/tst/reflect.tst
--- a/tst/reflect.tst
+++ b/tst/reflect.tst
@@ -1,6 +1,6 @@
 (herald reflect)
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from reflect.scm")
 
 (defprotocol reflect basic
diff --git a/tst/role_uniq.tst b/tst/role_uniq.tst
--- a/tst/role_uniq.tst
+++ b/tst/role_uniq.tst
@@ -1,6 +1,6 @@
 (herald "Role Unique Origination")
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from role_uniq.scm")
 
 (defprotocol blanchet basic
diff --git a/tst/rule-order.tst b/tst/rule-order.tst
--- a/tst/rule-order.tst
+++ b/tst/rule-order.tst
@@ -1,6 +1,6 @@
 (herald rule-order)
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from rule-order.scm")
 
 (defprotocol rule-order basic
diff --git a/tst/staticdh.tst b/tst/staticdh.tst
--- a/tst/staticdh.tst
+++ b/tst/staticdh.tst
@@ -1,6 +1,6 @@
 (herald "Static DH key exchange" (algebra diffie-hellman))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from staticdh.scm")
 
 (defprotocol staticdh1 diffie-hellman
diff --git a/tst/station.tst b/tst/station.tst
--- a/tst/station.tst
+++ b/tst/station.tst
@@ -1,6 +1,6 @@
 (herald "Station-to-station protocol" (algebra diffie-hellman))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from station.scm")
 
 (defprotocol station-to-station diffie-hellman
diff --git a/tst/station2.tst b/tst/station2.tst
--- a/tst/station2.tst
+++ b/tst/station2.tst
@@ -1,6 +1,6 @@
 (herald "Station-to-station protocol" (algebra diffie-hellman))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from station2.scm")
 
 (defprotocol station-to-station diffie-hellman
diff --git a/tst/subsort_test.tst b/tst/subsort_test.tst
--- a/tst/subsort_test.tst
+++ b/tst/subsort_test.tst
@@ -2,7 +2,7 @@
   (comment "First, third, and fourth skeletons should have a shape,"
     "second should be dead."))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from subsort_test.scm")
 
 (defprotocol subsorttest basic
diff --git a/tst/test_small.tst b/tst/test_small.tst
--- a/tst/test_small.tst
+++ b/tst/test_small.tst
@@ -1,6 +1,6 @@
 (herald "small test" (algebra diffie-hellman))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from test_small.scm")
 
 (defprotocol test diffie-hellman
diff --git a/tst/trust-anchor.tst b/tst/trust-anchor.tst
--- a/tst/trust-anchor.tst
+++ b/tst/trust-anchor.tst
@@ -1,7 +1,7 @@
 (herald trust-anchor
   (comment "Tests rule application on initial skeleton"))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from trust-anchor.scm")
 
 (defprotocol trust-anchor basic
diff --git a/tst/unilateral.tst b/tst/unilateral.tst
--- a/tst/unilateral.tst
+++ b/tst/unilateral.tst
@@ -1,6 +1,6 @@
 (herald unilateral)
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from unilateral.scm")
 
 (defprotocol unilateral basic
diff --git a/tst/uniq-gen-test.tst b/tst/uniq-gen-test.tst
--- a/tst/uniq-gen-test.tst
+++ b/tst/uniq-gen-test.tst
@@ -1,7 +1,7 @@
 (herald "Unique generation test protocols."
   (comment "Skeletons 2, 4, and 7 should have no shapes."))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from uniq-gen-test.scm")
 
 (defprotocol uniqgentest basic
diff --git a/tst/woolam.tst b/tst/woolam.tst
--- a/tst/woolam.tst
+++ b/tst/woolam.tst
@@ -1,6 +1,6 @@
 (herald "Woo-Lam Protocol")
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from woolam.scm")
 
 (defprotocol woolam basic
diff --git a/tst/wrap_decrypt.tst b/tst/wrap_decrypt.tst
--- a/tst/wrap_decrypt.tst
+++ b/tst/wrap_decrypt.tst
@@ -1,6 +1,6 @@
 (herald wrap-decrypt (bound 10))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from wrap_decrypt.lsp")
 (comment "Strand count bounded at 10")
 
diff --git a/tst/yahalom.tst b/tst/yahalom.tst
--- a/tst/yahalom.tst
+++ b/tst/yahalom.tst
@@ -1,7 +1,7 @@
 (herald "Yahalom Protocol with Forwarding Removed"
   (algebra diffie-hellman) (bound 12))
 
-(comment "CPSA 3.6.4")
+(comment "CPSA 3.6.5")
 (comment "All input read from yahalom.scm")
 
 (defprotocol yahalom diffie-hellman