    (herald
      "Yahalom Protocol with Forwarding Removed, using fnof to emulate ltk function"
      (bound 12))
    (comment "CPSA 3.6.2")
    (comment "All input read from fnof_yahalom.scm")

Trees: 0 4 10 15.

Tree 0.

    (defprotocol yahalom basic
      (defrole init
        (vars (a b c name) (n-a n-b text) (ltkac k skey))
        (trace (init (cat c ltkac)) (send (cat a n-a))
          (recv (enc b k n-a n-b ltkac)) (send (enc n-b k)))
        (fn-of ("ltk" (ltkac (cat a c))) ("ltk-inv" ((cat a c) ltkac))))
      (defrole resp
        (vars (b a c name) (n-a n-b text) (ltkac ltkbc k skey))
        (trace (init (cat c ltkac)) (recv (cat a n-a))
          (send (cat b (enc a n-a n-b ltkbc))) (recv (enc a k ltkbc))
          (recv (enc n-b k)))
        (fn-of ("ltk" (ltkac (cat a c)) (ltkbc (cat b c)))
          ("ltk-inv" ((cat a c) ltkac) ((cat b c) ltkbc))))
      (defrole serv
        (vars (c a b name) (n-a n-b text) (ltkac ltkbc k skey))
        (trace (init c) (recv (cat b (enc a n-a n-b ltkbc)))
          (send (enc b k n-a n-b ltkac)) (send (enc a k ltkbc)))
        (uniq-orig k)
        (fn-of ("ltk" (ltkac (cat a c)) (ltkbc (cat b c)))
          ("ltk-inv" ((cat a c) ltkac) ((cat b c) ltkbc)))))

Item 0, Child: 1.

    (defskeleton yahalom
      (vars (n-b n-a text) (a b c name) (ltkac ltkbc k skey))
      (defstrand resp 4 (n-a n-a) (n-b n-b) (b b) (a a) (c c) (ltkac ltkac)
        (ltkbc ltkbc) (k k))
      (fn-of ("ltk" (ltkac (cat a c)) (ltkbc (cat b c)))
        ("ltk-inv" ((cat a c) ltkac) ((cat b c) ltkbc)))
      (non-orig ltkac ltkbc)
      (uniq-orig n-b)
      (label 0)
      (unrealized (0 3))
      (origs (n-b (0 2)))
      (comment "1 in cohort - 1 not yet seen"))

Item 1, Parent: 0, Children: 2 3.

    (defskeleton yahalom
      (vars (n-b n-a n-a-0 n-b-0 text) (a b c name) (ltkac ltkbc k skey))
      (defstrand resp 4 (n-a n-a) (n-b n-b) (b b) (a a) (c c) (ltkac ltkac)
        (ltkbc ltkbc) (k k))
      (defstrand serv 4 (n-a n-a-0) (n-b n-b-0) (c c) (a a) (b b)
        (ltkac ltkac) (ltkbc ltkbc) (k k))
      (precedes ((1 3) (0 3)))
      (fn-of ("ltk" (ltkbc (cat b c)) (ltkac (cat a c)))
        ("ltk-inv" ((cat b c) ltkbc) ((cat a c) ltkac)))
      (non-orig ltkac ltkbc)
      (uniq-orig n-b k)
      (operation encryption-test (added-strand serv 4) (enc a k ltkbc)
        (0 3))
      (label 1)
      (parent 0)
      (unrealized (1 1))
      (comment "2 in cohort - 2 not yet seen"))

Item 2, Parent: 1.

    (defskeleton yahalom
      (vars (n-b n-a text) (a b c name) (ltkac ltkbc k skey))
      (defstrand resp 4 (n-a n-a) (n-b n-b) (b b) (a a) (c c) (ltkac ltkac)
        (ltkbc ltkbc) (k k))
      (defstrand serv 4 (n-a n-a) (n-b n-b) (c c) (a a) (b b) (ltkac ltkac)
        (ltkbc ltkbc) (k k))
      (precedes ((0 2) (1 1)) ((1 3) (0 3)))
      (fn-of ("ltk" (ltkac (cat a c)) (ltkbc (cat b c)))
        ("ltk-inv" ((cat a c) ltkac) ((cat b c) ltkbc)))
      (non-orig ltkac ltkbc)
      (uniq-orig n-b k)
      (operation encryption-test (displaced 2 0 resp 3)
        (enc a n-a-0 n-b-0 ltkbc) (1 1))
      (label 2)
      (parent 1)
      (unrealized)
      (shape)
      (maps
        ((0)
          ((a a) (b b) (c c) (n-b n-b) (ltkac ltkac) (ltkbc ltkbc) (n-a n-a)
            (k k))))
      (origs (k (1 2)) (n-b (0 2))))

Item 3, Parent: 1.

    (defskeleton yahalom
      (vars (n-b n-a n-a-0 n-b-0 text) (a b c name) (ltkac ltkbc k skey))
      (defstrand resp 4 (n-a n-a) (n-b n-b) (b b) (a a) (c c) (ltkac ltkac)
        (ltkbc ltkbc) (k k))
      (defstrand serv 4 (n-a n-a-0) (n-b n-b-0) (c c) (a a) (b b)
        (ltkac ltkac) (ltkbc ltkbc) (k k))
      (defstrand resp 3 (n-a n-a-0) (n-b n-b-0) (b b) (a a) (c c)
        (ltkac ltkac) (ltkbc ltkbc))
      (precedes ((1 3) (0 3)) ((2 2) (1 1)))
      (fn-of ("ltk" (ltkac (cat a c)) (ltkbc (cat b c)))
        ("ltk-inv" ((cat a c) ltkac) ((cat b c) ltkbc)))
      (non-orig ltkac ltkbc)
      (uniq-orig n-b k)
      (operation encryption-test (added-strand resp 3)
        (enc a n-a-0 n-b-0 ltkbc) (1 1))
      (label 3)
      (parent 1)
      (unrealized)
      (shape)
      (maps
        ((0)
          ((a a) (b b) (c c) (n-b n-b) (ltkac ltkac) (ltkbc ltkbc) (n-a n-a)
            (k k))))
      (origs (k (1 2)) (n-b (0 2))))

Tree 4.

    (defprotocol yahalom basic
      (defrole init
        (vars (a b c name) (n-a n-b text) (ltkac k skey))
        (trace (init (cat c ltkac)) (send (cat a n-a))
          (recv (enc b k n-a n-b ltkac)) (send (enc n-b k)))
        (fn-of ("ltk" (ltkac (cat a c))) ("ltk-inv" ((cat a c) ltkac))))
      (defrole resp
        (vars (b a c name) (n-a n-b text) (ltkac ltkbc k skey))
        (trace (init (cat c ltkac)) (recv (cat a n-a))
          (send (cat b (enc a n-a n-b ltkbc))) (recv (enc a k ltkbc))
          (recv (enc n-b k)))
        (fn-of ("ltk" (ltkac (cat a c)) (ltkbc (cat b c)))
          ("ltk-inv" ((cat a c) ltkac) ((cat b c) ltkbc))))
      (defrole serv
        (vars (c a b name) (n-a n-b text) (ltkac ltkbc k skey))
        (trace (init c) (recv (cat b (enc a n-a n-b ltkbc)))
          (send (enc b k n-a n-b ltkac)) (send (enc a k ltkbc)))
        (uniq-orig k)
        (fn-of ("ltk" (ltkac (cat a c)) (ltkbc (cat b c)))
          ("ltk-inv" ((cat a c) ltkac) ((cat b c) ltkbc)))))

Item 4, Child: 5.

    (defskeleton yahalom
      (vars (n-b n-a text) (a b c name) (ltkac ltkbc k skey))
      (defstrand resp 4 (n-a n-a) (n-b n-b) (b b) (a a) (c c) (ltkac ltkac)
        (ltkbc ltkbc) (k k))
      (deflistener k)
      (fn-of ("ltk" (ltkac (cat a c)) (ltkbc (cat b c)))
        ("ltk-inv" ((cat a c) ltkac) ((cat b c) ltkbc)))
      (non-orig ltkac ltkbc)
      (uniq-orig n-b)
      (label 4)
      (unrealized (0 3))
      (origs (n-b (0 2)))
      (comment "1 in cohort - 1 not yet seen"))

Item 5, Parent: 4, Children: 6 7.

    (defskeleton yahalom
      (vars (n-b n-a n-a-0 n-b-0 text) (a b c name) (ltkac ltkbc k skey))
      (defstrand resp 4 (n-a n-a) (n-b n-b) (b b) (a a) (c c) (ltkac ltkac)
        (ltkbc ltkbc) (k k))
      (deflistener k)
      (defstrand serv 4 (n-a n-a-0) (n-b n-b-0) (c c) (a a) (b b)
        (ltkac ltkac) (ltkbc ltkbc) (k k))
      (precedes ((2 2) (1 0)) ((2 3) (0 3)))
      (fn-of ("ltk" (ltkbc (cat b c)) (ltkac (cat a c)))
        ("ltk-inv" ((cat b c) ltkbc) ((cat a c) ltkac)))
      (non-orig ltkac ltkbc)
      (uniq-orig n-b k)
      (operation encryption-test (added-strand serv 4) (enc a k ltkbc)
        (0 3))
      (label 5)
      (parent 4)
      (unrealized (1 0) (2 1))
      (comment "2 in cohort - 2 not yet seen"))

Item 6, Parent: 5, Child: 8.

    (defskeleton yahalom
      (vars (n-b n-a text) (a b c name) (ltkac ltkbc k skey))
      (defstrand resp 4 (n-a n-a) (n-b n-b) (b b) (a a) (c c) (ltkac ltkac)
        (ltkbc ltkbc) (k k))
      (deflistener k)
      (defstrand serv 4 (n-a n-a) (n-b n-b) (c c) (a a) (b b) (ltkac ltkac)
        (ltkbc ltkbc) (k k))
      (precedes ((0 2) (2 1)) ((2 2) (1 0)) ((2 3) (0 3)))
      (fn-of ("ltk" (ltkac (cat a c)) (ltkbc (cat b c)))
        ("ltk-inv" ((cat a c) ltkac) ((cat b c) ltkbc)))
      (non-orig ltkac ltkbc)
      (uniq-orig n-b k)
      (operation encryption-test (displaced 3 0 resp 3)
        (enc a n-a-0 n-b-0 ltkbc) (2 1))
      (label 6)
      (parent 5)
      (unrealized (1 0))
      (comment "1 in cohort - 1 not yet seen"))

Item 7, Parent: 5, Child: 9.

    (defskeleton yahalom
      (vars (n-b n-a n-a-0 n-b-0 text) (a b c name) (ltkac ltkbc k skey))
      (defstrand resp 4 (n-a n-a) (n-b n-b) (b b) (a a) (c c) (ltkac ltkac)
        (ltkbc ltkbc) (k k))
      (deflistener k)
      (defstrand serv 4 (n-a n-a-0) (n-b n-b-0) (c c) (a a) (b b)
        (ltkac ltkac) (ltkbc ltkbc) (k k))
      (defstrand resp 3 (n-a n-a-0) (n-b n-b-0) (b b) (a a) (c c)
        (ltkac ltkac) (ltkbc ltkbc))
      (precedes ((2 2) (1 0)) ((2 3) (0 3)) ((3 2) (2 1)))
      (fn-of ("ltk" (ltkac (cat a c)) (ltkbc (cat b c)))
        ("ltk-inv" ((cat a c) ltkac) ((cat b c) ltkbc)))
      (non-orig ltkac ltkbc)
      (uniq-orig n-b k)
      (operation encryption-test (added-strand resp 3)
        (enc a n-a-0 n-b-0 ltkbc) (2 1))
      (label 7)
      (parent 5)
      (unrealized (1 0))
      (comment "1 in cohort - 1 not yet seen"))

Item 8, Parent: 6.

    (defskeleton yahalom
      (vars (n-b n-a text) (a b c name) (ltkac ltkbc k skey))
      (defstrand resp 4 (n-a n-a) (n-b n-b) (b b) (a a) (c c) (ltkac ltkac)
        (ltkbc ltkbc) (k k))
      (deflistener k)
      (defstrand serv 4 (n-a n-a) (n-b n-b) (c c) (a a) (b b) (ltkac ltkac)
        (ltkbc ltkbc) (k k))
      (precedes ((0 2) (2 1)) ((2 3) (0 3)) ((2 3) (1 0)))
      (fn-of ("ltk" (ltkbc (cat b c)) (ltkac (cat a c)))
        ("ltk-inv" ((cat b c) ltkbc) ((cat a c) ltkac)))
      (non-orig ltkac ltkbc)
      (uniq-orig n-b k)
      (operation nonce-test (displaced 3 2 serv 4) k (1 0)
        (enc b k n-a n-b ltkac))
      (label 8)
      (parent 6)
      (unrealized (1 0))
      (comment "empty cohort"))

Item 9, Parent: 7.

    (defskeleton yahalom
      (vars (n-b n-a n-a-0 n-b-0 text) (a b c name) (ltkac ltkbc k skey))
      (defstrand resp 4 (n-a n-a) (n-b n-b) (b b) (a a) (c c) (ltkac ltkac)
        (ltkbc ltkbc) (k k))
      (deflistener k)
      (defstrand serv 4 (n-a n-a-0) (n-b n-b-0) (c c) (a a) (b b)
        (ltkac ltkac) (ltkbc ltkbc) (k k))
      (defstrand resp 3 (n-a n-a-0) (n-b n-b-0) (b b) (a a) (c c)
        (ltkac ltkac) (ltkbc ltkbc))
      (precedes ((2 3) (0 3)) ((2 3) (1 0)) ((3 2) (2 1)))
      (fn-of ("ltk" (ltkbc (cat b c)) (ltkac (cat a c)))
        ("ltk-inv" ((cat b c) ltkbc) ((cat a c) ltkac)))
      (non-orig ltkac ltkbc)
      (uniq-orig n-b k)
      (operation nonce-test (displaced 4 2 serv 4) k (1 0)
        (enc b k n-a-0 n-b-0 ltkac))
      (label 9)
      (parent 7)
      (unrealized (1 0))
      (comment "empty cohort"))

Tree 10.

    (defprotocol yahalom2 basic
      (defrole init
        (vars (a b name) (n-a n-b text) (ltkac ltkbc k skey))
        (trace (send (cat a n-a (hash ltkbc)))
          (recv (enc b k n-a n-b ltkac)) (send (enc n-b k))))
      (defrole resp
        (vars (b a c name) (n-a n-b text) (ltkac ltkbc k skey))
        (trace (recv (cat a n-a))
          (send (cat b (enc a n-a n-b ltkbc) (hash c ltkac)))
          (recv (enc a k ltkbc)) (recv (enc n-b k)))
        (fn-of ("ltk" (ltkac (cat a c)) (ltkbc (cat b c)))))
      (defrole serv
        (vars (c a b name) (n-a n-b text) (ltkac ltkbc k skey))
        (trace (recv (cat b (enc a n-a n-b ltkbc)))
          (send (cat (hash c) (enc b k n-a n-b ltkac)))
          (send (enc a k ltkbc)))
        (uniq-orig k)
        (fn-of ("ltk" (ltkac (cat a c)) (ltkbc (cat b c))))))

Item 10, Child: 11.

    (defskeleton yahalom2
      (vars (n-b n-a text) (a b c name) (ltkac ltkbc k skey))
      (defstrand resp 4 (n-a n-a) (n-b n-b) (b b) (a a) (c c) (ltkac ltkac)
        (ltkbc ltkbc) (k k))
      (fn-of ("ltk" (ltkac (cat a c)) (ltkbc (cat b c))))
      (non-orig ltkac ltkbc)
      (uniq-orig n-b)
      (label 10)
      (unrealized (0 2) (0 3))
      (origs (n-b (0 1)))
      (comment "1 in cohort - 1 not yet seen"))

Item 11, Parent: 10, Children: 12 13.

    (defskeleton yahalom2
      (vars (n-b n-a n-a-0 n-b-0 text) (a b c c-0 b-0 name)
        (ltkac ltkbc k ltkac-0 skey))
      (defstrand resp 4 (n-a n-a) (n-b n-b) (b b) (a a) (c c) (ltkac ltkac)
        (ltkbc ltkbc) (k k))
      (defstrand serv 3 (n-a n-a-0) (n-b n-b-0) (c c-0) (a a) (b b-0)
        (ltkac ltkac-0) (ltkbc ltkbc) (k k))
      (precedes ((1 2) (0 2)))
      (fn-of
        ("ltk" (ltkac-0 (cat a c-0)) (ltkbc (cat b-0 c-0)) (ltkac (cat a c))
          (ltkbc (cat b c))))
      (non-orig ltkac ltkbc)
      (uniq-orig n-b k)
      (operation encryption-test (added-strand serv 3) (enc a k ltkbc)
        (0 2))
      (label 11)
      (parent 10)
      (unrealized (0 3) (1 0))
      (comment "2 in cohort - 2 not yet seen"))

Item 12, Parent: 11.

    (defskeleton yahalom2
      (vars (n-b n-a text) (a b c c-0 b-0 name)
        (ltkac ltkbc k ltkac-0 skey))
      (defstrand resp 4 (n-a n-a) (n-b n-b) (b b) (a a) (c c) (ltkac ltkac)
        (ltkbc ltkbc) (k k))
      (defstrand serv 3 (n-a n-a) (n-b n-b) (c c-0) (a a) (b b-0)
        (ltkac ltkac-0) (ltkbc ltkbc) (k k))
      (precedes ((0 1) (1 0)) ((1 2) (0 2)))
      (fn-of
        ("ltk" (ltkac (cat a c)) (ltkbc (cat b c)) (ltkac-0 (cat a c-0))
          (ltkbc (cat b-0 c-0))))
      (non-orig ltkac ltkbc)
      (uniq-orig n-b k)
      (operation encryption-test (displaced 2 0 resp 2)
        (enc a n-a-0 n-b-0 ltkbc) (1 0))
      (label 12)
      (parent 11)
      (unrealized)
      (shape)
      (maps
        ((0)
          ((a a) (b b) (c c) (n-b n-b) (ltkac ltkac) (ltkbc ltkbc) (n-a n-a)
            (k k))))
      (origs (k (1 1)) (n-b (0 1))))

Item 13, Parent: 11, Child: 14.

    (defskeleton yahalom2
      (vars (n-b n-a n-a-0 n-b-0 text) (a b c c-0 b-0 b-1 c-1 name)
        (ltkac ltkbc k ltkac-0 ltkac-1 skey))
      (defstrand resp 4 (n-a n-a) (n-b n-b) (b b) (a a) (c c) (ltkac ltkac)
        (ltkbc ltkbc) (k k))
      (defstrand serv 3 (n-a n-a-0) (n-b n-b-0) (c c-0) (a a) (b b-0)
        (ltkac ltkac-0) (ltkbc ltkbc) (k k))
      (defstrand resp 2 (n-a n-a-0) (n-b n-b-0) (b b-1) (a a) (c c-1)
        (ltkac ltkac-1) (ltkbc ltkbc))
      (precedes ((1 2) (0 2)) ((2 1) (1 0)))
      (fn-of
        ("ltk" (ltkac-1 (cat a c-1)) (ltkbc (cat b-1 c-1))
          (ltkac-0 (cat a c-0)) (ltkbc (cat b-0 c-0)) (ltkac (cat a c))
          (ltkbc (cat b c))))
      (non-orig ltkac ltkbc)
      (uniq-orig n-b k)
      (operation encryption-test (added-strand resp 2)
        (enc a n-a-0 n-b-0 ltkbc) (1 0))
      (label 13)
      (parent 11)
      (unrealized (0 3))
      (comment "1 in cohort - 1 not yet seen"))

Item 14, Parent: 13.

    (defskeleton yahalom2
      (vars (n-b n-a n-a-0 n-b-0 text) (a b c c-0 b-0 b-1 c-1 c-2 b-2 name)
        (ltkac ltkbc k ltkac-0 ltkac-1 ltkac-2 k-0 skey))
      (defstrand resp 4 (n-a n-a) (n-b n-b) (b b) (a a) (c c) (ltkac ltkac)
        (ltkbc ltkbc) (k k))
      (defstrand serv 3 (n-a n-a-0) (n-b n-b-0) (c c-0) (a a) (b b-0)
        (ltkac ltkac-0) (ltkbc ltkbc) (k k))
      (defstrand resp 2 (n-a n-a-0) (n-b n-b-0) (b b-1) (a a) (c c-1)
        (ltkac ltkac-1) (ltkbc ltkbc))
      (defstrand serv 2 (n-a n-a) (n-b n-b) (c c-2) (a a) (b b-2)
        (ltkac ltkac-2) (ltkbc ltkbc) (k k-0))
      (precedes ((0 1) (3 0)) ((1 2) (0 2)) ((2 1) (1 0)) ((3 1) (0 3)))
      (fn-of
        ("ltk" (ltkac-2 (cat a c-2)) (ltkbc (cat b-2 c-2))
          (ltkac-1 (cat a c-1)) (ltkbc (cat b-1 c-1)) (ltkac-0 (cat a c-0))
          (ltkbc (cat b-0 c-0)) (ltkac (cat a c)) (ltkbc (cat b c))))
      (non-orig ltkac ltkbc)
      (uniq-orig n-b k k-0)
      (operation nonce-test (added-strand serv 2) n-b (0 3)
        (enc a n-a n-b ltkbc))
      (label 14)
      (parent 13)
      (unrealized)
      (shape)
      (maps
        ((0)
          ((a a) (b b) (c c) (n-b n-b) (ltkac ltkac) (ltkbc ltkbc) (n-a n-a)
            (k k))))
      (origs (k-0 (3 1)) (k (1 1)) (n-b (0 1))))

Tree 15.

    (defprotocol yahalom2 basic
      (defrole init
        (vars (a b name) (n-a n-b text) (ltkac ltkbc k skey))
        (trace (send (cat a n-a (hash ltkbc)))
          (recv (enc b k n-a n-b ltkac)) (send (enc n-b k))))
      (defrole resp
        (vars (b a c name) (n-a n-b text) (ltkac ltkbc k skey))
        (trace (recv (cat a n-a))
          (send (cat b (enc a n-a n-b ltkbc) (hash c ltkac)))
          (recv (enc a k ltkbc)) (recv (enc n-b k)))
        (fn-of ("ltk" (ltkac (cat a c)) (ltkbc (cat b c)))))
      (defrole serv
        (vars (c a b name) (n-a n-b text) (ltkac ltkbc k skey))
        (trace (recv (cat b (enc a n-a n-b ltkbc)))
          (send (cat (hash c) (enc b k n-a n-b ltkac)))
          (send (enc a k ltkbc)))
        (uniq-orig k)
        (fn-of ("ltk" (ltkac (cat a c)) (ltkbc (cat b c))))))

Item 15, Child: 16.

    (defskeleton yahalom2
      (vars (n-b n-a text) (a b c name) (ltkac ltkbc k skey))
      (defstrand resp 4 (n-a n-a) (n-b n-b) (b b) (a a) (c c) (ltkac ltkac)
        (ltkbc ltkbc) (k k))
      (deflistener k)
      (fn-of ("ltk" (ltkac (cat a c)) (ltkbc (cat b c))))
      (non-orig ltkac ltkbc)
      (uniq-orig n-b)
      (label 15)
      (unrealized (0 2) (0 3))
      (origs (n-b (0 1)))
      (comment "1 in cohort - 1 not yet seen"))

Item 16, Parent: 15, Children: 17 18.

    (defskeleton yahalom2
      (vars (n-b n-a n-a-0 n-b-0 text) (a b c c-0 b-0 name)
        (ltkac ltkbc k ltkac-0 skey))
      (defstrand resp 4 (n-a n-a) (n-b n-b) (b b) (a a) (c c) (ltkac ltkac)
        (ltkbc ltkbc) (k k))
      (deflistener k)
      (defstrand serv 3 (n-a n-a-0) (n-b n-b-0) (c c-0) (a a) (b b-0)
        (ltkac ltkac-0) (ltkbc ltkbc) (k k))
      (precedes ((2 1) (1 0)) ((2 2) (0 2)))
      (fn-of
        ("ltk" (ltkac-0 (cat a c-0)) (ltkbc (cat b-0 c-0)) (ltkac (cat a c))
          (ltkbc (cat b c))))
      (non-orig ltkac ltkbc)
      (uniq-orig n-b k)
      (operation encryption-test (added-strand serv 3) (enc a k ltkbc)
        (0 2))
      (label 16)
      (parent 15)
      (unrealized (0 3) (2 0))
      (comment "2 in cohort - 2 not yet seen"))

Item 17, Parent: 16.

    (defskeleton yahalom2
      (vars (n-b n-a text) (a b c c-0 b-0 name)
        (ltkac ltkbc k ltkac-0 skey))
      (defstrand resp 4 (n-a n-a) (n-b n-b) (b b) (a a) (c c) (ltkac ltkac)
        (ltkbc ltkbc) (k k))
      (deflistener k)
      (defstrand serv 3 (n-a n-a) (n-b n-b) (c c-0) (a a) (b b-0)
        (ltkac ltkac-0) (ltkbc ltkbc) (k k))
      (precedes ((0 1) (2 0)) ((2 1) (1 0)) ((2 2) (0 2)))
      (fn-of
        ("ltk" (ltkac (cat a c)) (ltkbc (cat b c)) (ltkac-0 (cat a c-0))
          (ltkbc (cat b-0 c-0))))
      (non-orig ltkac ltkbc)
      (uniq-orig n-b k)
      (operation encryption-test (displaced 3 0 resp 2)
        (enc a n-a-0 n-b-0 ltkbc) (2 0))
      (label 17)
      (parent 16)
      (unrealized)
      (shape)
      (maps
        ((0 1)
          ((a a) (b b) (c c) (n-b n-b) (ltkac ltkac) (ltkbc ltkbc) (k k)
            (n-a n-a))))
      (origs (k (2 1)) (n-b (0 1))))

Item 18, Parent: 16, Child: 19.

    (defskeleton yahalom2
      (vars (n-b n-a n-a-0 n-b-0 text) (a b c c-0 b-0 b-1 c-1 name)
        (ltkac ltkbc k ltkac-0 ltkac-1 skey))
      (defstrand resp 4 (n-a n-a) (n-b n-b) (b b) (a a) (c c) (ltkac ltkac)
        (ltkbc ltkbc) (k k))
      (deflistener k)
      (defstrand serv 3 (n-a n-a-0) (n-b n-b-0) (c c-0) (a a) (b b-0)
        (ltkac ltkac-0) (ltkbc ltkbc) (k k))
      (defstrand resp 2 (n-a n-a-0) (n-b n-b-0) (b b-1) (a a) (c c-1)
        (ltkac ltkac-1) (ltkbc ltkbc))
      (precedes ((2 1) (1 0)) ((2 2) (0 2)) ((3 1) (2 0)))
      (fn-of
        ("ltk" (ltkac-1 (cat a c-1)) (ltkbc (cat b-1 c-1))
          (ltkac-0 (cat a c-0)) (ltkbc (cat b-0 c-0)) (ltkac (cat a c))
          (ltkbc (cat b c))))
      (non-orig ltkac ltkbc)
      (uniq-orig n-b k)
      (operation encryption-test (added-strand resp 2)
        (enc a n-a-0 n-b-0 ltkbc) (2 0))
      (label 18)
      (parent 16)
      (unrealized (0 3))
      (comment "1 in cohort - 1 not yet seen"))

Item 19, Parent: 18.

    (defskeleton yahalom2
      (vars (n-b n-a n-a-0 n-b-0 text) (a b c c-0 b-0 b-1 c-1 c-2 b-2 name)
        (ltkac ltkbc k ltkac-0 ltkac-1 ltkac-2 k-0 skey))
      (defstrand resp 4 (n-a n-a) (n-b n-b) (b b) (a a) (c c) (ltkac ltkac)
        (ltkbc ltkbc) (k k))
      (deflistener k)
      (defstrand serv 3 (n-a n-a-0) (n-b n-b-0) (c c-0) (a a) (b b-0)
        (ltkac ltkac-0) (ltkbc ltkbc) (k k))
      (defstrand resp 2 (n-a n-a-0) (n-b n-b-0) (b b-1) (a a) (c c-1)
        (ltkac ltkac-1) (ltkbc ltkbc))
      (defstrand serv 2 (n-a n-a) (n-b n-b) (c c-2) (a a) (b b-2)
        (ltkac ltkac-2) (ltkbc ltkbc) (k k-0))
      (precedes ((0 1) (4 0)) ((2 1) (1 0)) ((2 2) (0 2)) ((3 1) (2 0))
        ((4 1) (0 3)))
      (fn-of
        ("ltk" (ltkac-2 (cat a c-2)) (ltkbc (cat b-2 c-2))
          (ltkac-1 (cat a c-1)) (ltkbc (cat b-1 c-1)) (ltkac-0 (cat a c-0))
          (ltkbc (cat b-0 c-0)) (ltkac (cat a c)) (ltkbc (cat b c))))
      (non-orig ltkac ltkbc)
      (uniq-orig n-b k k-0)
      (operation nonce-test (added-strand serv 2) n-b (0 3)
        (enc a n-a n-b ltkbc))
      (label 19)
      (parent 18)
      (unrealized)
      (shape)
      (maps
        ((0 1)
          ((a a) (b b) (c c) (n-b n-b) (ltkac ltkac) (ltkbc ltkbc) (k k)
            (n-a n-a))))
      (origs (k-0 (4 1)) (k (2 1)) (n-b (0 1))))