author | paulson |
Fri, 29 Nov 1996 18:03:21 +0100 | |
changeset 2284 | 80ebd1a213fd |
parent 2264 | f298678bd54a |
child 2323 | 3ae9b0ccee21 |
permissions | -rw-r--r-- |
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
1 |
(* Title: HOL/Auth/Yahalom2 |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
2 |
ID: $Id$ |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
3 |
Author: Lawrence C Paulson, Cambridge University Computer Laboratory |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
4 |
Copyright 1996 University of Cambridge |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
5 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
6 |
Inductive relation "yahalom" for the Yahalom protocol, Variant 2. |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
7 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
8 |
This version trades encryption of NB for additional explicitness in YM3. |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
9 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
10 |
From page 259 of |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
11 |
Burrows, Abadi and Needham. A Logic of Authentication. |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
12 |
Proc. Royal Soc. 426 (1989) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
13 |
*) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
14 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
15 |
open Yahalom2; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
16 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
17 |
proof_timing:=true; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
18 |
HOL_quantifiers := false; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
19 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
20 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
21 |
(*Weak liveness: there are traces that reach the end*) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
22 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
23 |
goal thy |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
24 |
"!!A B. [| A ~= B; A ~= Server; B ~= Server |] \ |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
25 |
\ ==> EX X NB K. EX evs: yahalom lost. \ |
2284
80ebd1a213fd
Swapped arguments of Crypt (for clarity and because it is conventional)
paulson
parents:
2264
diff
changeset
|
26 |
\ Says A B {|X, Crypt K (Nonce NB)|} : set_of_list evs"; |
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
27 |
by (REPEAT (resolve_tac [exI,bexI] 1)); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
28 |
by (rtac (yahalom.Nil RS yahalom.YM1 RS yahalom.YM2 RS yahalom.YM3 RS yahalom.YM4) 2); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
29 |
by (ALLGOALS (simp_tac (!simpset setsolver safe_solver))); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
30 |
by (ALLGOALS Fast_tac); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
31 |
result(); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
32 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
33 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
34 |
(**** Inductive proofs about yahalom ****) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
35 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
36 |
(*Monotonicity*) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
37 |
goal thy "!!evs. lost' <= lost ==> yahalom lost' <= yahalom lost"; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
38 |
by (rtac subsetI 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
39 |
by (etac yahalom.induct 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
40 |
by (REPEAT_FIRST |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
41 |
(best_tac (!claset addIs (impOfSubs (sees_mono RS analz_mono RS synth_mono) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
42 |
:: yahalom.intrs)))); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
43 |
qed "yahalom_mono"; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
44 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
45 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
46 |
(*Nobody sends themselves messages*) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
47 |
goal thy "!!evs. evs: yahalom lost ==> ALL A X. Says A A X ~: set_of_list evs"; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
48 |
by (etac yahalom.induct 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
49 |
by (Auto_tac()); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
50 |
qed_spec_mp "not_Says_to_self"; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
51 |
Addsimps [not_Says_to_self]; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
52 |
AddSEs [not_Says_to_self RSN (2, rev_notE)]; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
53 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
54 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
55 |
(** For reasoning about the encrypted portion of messages **) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
56 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
57 |
(*Lets us treat YM4 using a similar argument as for the Fake case.*) |
2284
80ebd1a213fd
Swapped arguments of Crypt (for clarity and because it is conventional)
paulson
parents:
2264
diff
changeset
|
58 |
goal thy "!!evs. Says S A {|NB, Crypt (shrK A) Y, X|} : set_of_list evs ==> \ |
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
59 |
\ X : analz (sees lost Spy evs)"; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
60 |
by (fast_tac (!claset addSDs [Says_imp_sees_Spy RS analz.Inj]) 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
61 |
qed "YM4_analz_sees_Spy"; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
62 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
63 |
bind_thm ("YM4_parts_sees_Spy", |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
64 |
YM4_analz_sees_Spy RS (impOfSubs analz_subset_parts)); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
65 |
|
2155 | 66 |
(*Relates to both YM4 and Oops*) |
2284
80ebd1a213fd
Swapped arguments of Crypt (for clarity and because it is conventional)
paulson
parents:
2264
diff
changeset
|
67 |
goal thy "!!evs. Says S A {|NB, Crypt (shrK A) {|B, K, NA|}, X|} \ |
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
68 |
\ : set_of_list evs ==> \ |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
69 |
\ K : parts (sees lost Spy evs)"; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
70 |
by (fast_tac (!claset addSEs partsEs |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
71 |
addSDs [Says_imp_sees_Spy RS parts.Inj]) 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
72 |
qed "YM4_Key_parts_sees_Spy"; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
73 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
74 |
(*We instantiate the variable to "lost". Leaving it as a Var makes proofs |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
75 |
harder: the simplifier does less.*) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
76 |
val parts_Fake_tac = |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
77 |
forw_inst_tac [("lost","lost")] YM4_parts_sees_Spy 6 THEN |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
78 |
forw_inst_tac [("lost","lost")] YM4_Key_parts_sees_Spy 7; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
79 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
80 |
(*For proving the easier theorems about X ~: parts (sees lost Spy evs) *) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
81 |
fun parts_induct_tac i = SELECT_GOAL |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
82 |
(DETERM (etac yahalom.induct 1 THEN parts_Fake_tac THEN |
2170 | 83 |
(*Fake message*) |
84 |
TRY (best_tac (!claset addDs [impOfSubs analz_subset_parts, |
|
85 |
impOfSubs Fake_parts_insert] |
|
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
86 |
addss (!simpset)) 2)) THEN |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
87 |
(*Base case*) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
88 |
fast_tac (!claset addss (!simpset)) 1 THEN |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
89 |
ALLGOALS Asm_simp_tac) i; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
90 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
91 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
92 |
(** Theorems of the form X ~: parts (sees lost Spy evs) imply that NOBODY |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
93 |
sends messages containing X! **) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
94 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
95 |
(*Spy never sees another agent's shared key! (unless it is leaked at start)*) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
96 |
goal thy |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
97 |
"!!evs. [| evs : yahalom lost; A ~: lost |] \ |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
98 |
\ ==> Key (shrK A) ~: parts (sees lost Spy evs)"; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
99 |
by (parts_induct_tac 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
100 |
by (Auto_tac()); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
101 |
qed "Spy_not_see_shrK"; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
102 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
103 |
bind_thm ("Spy_not_analz_shrK", |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
104 |
[analz_subset_parts, Spy_not_see_shrK] MRS contra_subsetD); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
105 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
106 |
Addsimps [Spy_not_see_shrK, Spy_not_analz_shrK]; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
107 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
108 |
(*We go to some trouble to preserve R in the 3rd and 4th subgoals |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
109 |
As usual fast_tac cannot be used because it uses the equalities too soon*) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
110 |
val major::prems = |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
111 |
goal thy "[| Key (shrK A) : parts (sees lost Spy evs); \ |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
112 |
\ evs : yahalom lost; \ |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
113 |
\ A:lost ==> R \ |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
114 |
\ |] ==> R"; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
115 |
by (rtac ccontr 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
116 |
by (rtac ([major, Spy_not_see_shrK] MRS rev_notE) 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
117 |
by (swap_res_tac prems 2); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
118 |
by (ALLGOALS (fast_tac (!claset addIs prems))); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
119 |
qed "Spy_see_shrK_E"; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
120 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
121 |
bind_thm ("Spy_analz_shrK_E", |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
122 |
analz_subset_parts RS subsetD RS Spy_see_shrK_E); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
123 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
124 |
AddSEs [Spy_see_shrK_E, Spy_analz_shrK_E]; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
125 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
126 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
127 |
(*** Future keys can't be seen or used! ***) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
128 |
|
2160 | 129 |
(*Nobody can have SEEN keys that will be generated in the future. *) |
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
130 |
goal thy "!!evs. evs : yahalom lost ==> \ |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
131 |
\ length evs <= length evs' --> \ |
2160 | 132 |
\ Key (newK evs') ~: parts (sees lost Spy evs)"; |
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
133 |
by (parts_induct_tac 1); |
2264
f298678bd54a
Weaking of injectivity assumptions for newK and newN:
paulson
parents:
2170
diff
changeset
|
134 |
by (REPEAT_FIRST (best_tac (!claset addEs [leD RS notE] |
f298678bd54a
Weaking of injectivity assumptions for newK and newN:
paulson
parents:
2170
diff
changeset
|
135 |
addDs [impOfSubs analz_subset_parts, |
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
136 |
impOfSubs parts_insert_subset_Un, |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
137 |
Suc_leD] |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
138 |
addss (!simpset)))); |
2160 | 139 |
qed_spec_mp "new_keys_not_seen"; |
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
140 |
Addsimps [new_keys_not_seen]; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
141 |
|
2160 | 142 |
(*Variant: old messages must contain old keys!*) |
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
143 |
goal thy |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
144 |
"!!evs. [| Says A B X : set_of_list evs; \ |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
145 |
\ Key (newK evt) : parts {X}; \ |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
146 |
\ evs : yahalom lost \ |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
147 |
\ |] ==> length evt < length evs"; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
148 |
by (rtac ccontr 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
149 |
by (dtac leI 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
150 |
by (fast_tac (!claset addSDs [new_keys_not_seen, Says_imp_sees_Spy] |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
151 |
addIs [impOfSubs parts_mono]) 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
152 |
qed "Says_imp_old_keys"; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
153 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
154 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
155 |
(*Nobody can have USED keys that will be generated in the future. |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
156 |
...very like new_keys_not_seen*) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
157 |
goal thy "!!evs. evs : yahalom lost ==> \ |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
158 |
\ length evs <= length evs' --> \ |
2160 | 159 |
\ newK evs' ~: keysFor (parts (sees lost Spy evs))"; |
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
160 |
by (parts_induct_tac 1); |
2170 | 161 |
by (dtac YM4_Key_parts_sees_Spy 5); |
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
162 |
(*YM1, YM2 and YM3*) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
163 |
by (EVERY (map (fast_tac (!claset addDs [Suc_leD] addss (!simpset))) [4,3,2])); |
2160 | 164 |
(*Fake and Oops: these messages send unknown (X) components*) |
165 |
by (EVERY |
|
166 |
(map (fast_tac |
|
2170 | 167 |
(!claset addDs [impOfSubs analz_subset_parts, |
168 |
impOfSubs (analz_subset_parts RS keysFor_mono), |
|
169 |
impOfSubs (parts_insert_subset_Un RS keysFor_mono), |
|
170 |
Suc_leD] |
|
2160 | 171 |
addss (!simpset))) [3,1])); |
172 |
(*YM4: if K was used then it had been seen, contradicting new_keys_not_seen*) |
|
173 |
by (fast_tac |
|
174 |
(!claset addSEs partsEs |
|
175 |
addSDs [Says_imp_sees_Spy RS parts.Inj] |
|
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
176 |
addEs [new_keys_not_seen RSN(2,rev_notE)] |
2160 | 177 |
addDs [Suc_leD]) 1); |
178 |
qed_spec_mp "new_keys_not_used"; |
|
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
179 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
180 |
bind_thm ("new_keys_not_analzd", |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
181 |
[analz_subset_parts RS keysFor_mono, |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
182 |
new_keys_not_used] MRS contra_subsetD); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
183 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
184 |
Addsimps [new_keys_not_used, new_keys_not_analzd]; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
185 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
186 |
|
2155 | 187 |
(*Describes the form of K when the Server sends this message. Useful for |
188 |
Oops as well as main secrecy property.*) |
|
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
189 |
goal thy |
2284
80ebd1a213fd
Swapped arguments of Crypt (for clarity and because it is conventional)
paulson
parents:
2264
diff
changeset
|
190 |
"!!evs. [| Says Server A {|NB', Crypt (shrK A) {|Agent B, K, NA|}, X|} \ |
2155 | 191 |
\ : set_of_list evs; \ |
192 |
\ evs : yahalom lost |] \ |
|
193 |
\ ==> (EX evt: yahalom lost. K = Key(newK evt)) & A ~= B"; |
|
194 |
by (etac rev_mp 1); |
|
195 |
by (etac yahalom.induct 1); |
|
196 |
by (ALLGOALS (fast_tac (!claset addss (!simpset)))); |
|
197 |
qed "Says_Server_message_form"; |
|
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
198 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
199 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
200 |
(*For proofs involving analz. We again instantiate the variable to "lost".*) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
201 |
val analz_Fake_tac = |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
202 |
dres_inst_tac [("lost","lost")] YM4_analz_sees_Spy 6 THEN |
2155 | 203 |
forw_inst_tac [("lost","lost")] Says_Server_message_form 7 THEN |
204 |
assume_tac 7 THEN Full_simp_tac 7 THEN |
|
205 |
REPEAT ((eresolve_tac [bexE,conjE] ORELSE' hyp_subst_tac) 7); |
|
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
206 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
207 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
208 |
(**** |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
209 |
The following is to prove theorems of the form |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
210 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
211 |
Key K : analz (insert (Key (newK evt)) (sees lost Spy evs)) ==> |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
212 |
Key K : analz (sees lost Spy evs) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
213 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
214 |
A more general formula must be proved inductively. |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
215 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
216 |
****) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
217 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
218 |
(** Session keys are not used to encrypt other session keys **) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
219 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
220 |
goal thy |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
221 |
"!!evs. evs : yahalom lost ==> \ |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
222 |
\ ALL K E. (Key K : analz (Key``(newK``E) Un (sees lost Spy evs))) = \ |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
223 |
\ (K : newK``E | Key K : analz (sees lost Spy evs))"; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
224 |
by (etac yahalom.induct 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
225 |
by analz_Fake_tac; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
226 |
by (REPEAT_FIRST (resolve_tac [allI, analz_image_newK_lemma])); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
227 |
by (ALLGOALS (*Takes 26 secs*) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
228 |
(asm_simp_tac |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
229 |
(!simpset addsimps ([insert_Key_singleton, insert_Key_image, pushKey_newK] |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
230 |
@ pushes) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
231 |
setloop split_tac [expand_if]))); |
2155 | 232 |
(*YM4, Fake*) |
233 |
by (EVERY (map spy_analz_tac [4, 2])); |
|
234 |
(*Oops, YM3, Base*) |
|
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
235 |
by (REPEAT (fast_tac (!claset addIs [image_eqI] addss (!simpset)) 1)); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
236 |
qed_spec_mp "analz_image_newK"; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
237 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
238 |
goal thy |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
239 |
"!!evs. evs : yahalom lost ==> \ |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
240 |
\ Key K : analz (insert (Key (newK evt)) (sees lost Spy evs)) = \ |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
241 |
\ (K = newK evt | Key K : analz (sees lost Spy evs))"; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
242 |
by (asm_simp_tac (HOL_ss addsimps [pushKey_newK, analz_image_newK, |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
243 |
insert_Key_singleton]) 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
244 |
by (Fast_tac 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
245 |
qed "analz_insert_Key_newK"; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
246 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
247 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
248 |
(*** The Key K uniquely identifies the Server's message. **) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
249 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
250 |
goal thy |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
251 |
"!!evs. evs : yahalom lost ==> \ |
2155 | 252 |
\ EX A' B' NA' NB' X'. ALL A B NA NB X. \ |
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
253 |
\ Says Server A \ |
2284
80ebd1a213fd
Swapped arguments of Crypt (for clarity and because it is conventional)
paulson
parents:
2264
diff
changeset
|
254 |
\ {|NB, Crypt (shrK A) {|Agent B, Key K, NA|}, X|} \ |
2155 | 255 |
\ : set_of_list evs --> A=A' & B=B' & NA=NA' & NB=NB' & X=X'"; |
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
256 |
by (etac yahalom.induct 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
257 |
by (ALLGOALS (asm_simp_tac (!simpset addsimps [all_conj_distrib]))); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
258 |
by (Step_tac 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
259 |
(*Remaining case: YM3*) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
260 |
by (expand_case_tac "K = ?y" 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
261 |
by (REPEAT (ares_tac [refl,exI,impI,conjI] 2)); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
262 |
(*...we assume X is a very new message, and handle this case by contradiction*) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
263 |
by (fast_tac (!claset addEs [Says_imp_old_keys RS less_irrefl] |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
264 |
delrules [conjI] (*prevent split-up into 4 subgoals*) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
265 |
addss (!simpset addsimps [parts_insertI])) 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
266 |
val lemma = result(); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
267 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
268 |
goal thy |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
269 |
"!!evs. [| Says Server A \ |
2284
80ebd1a213fd
Swapped arguments of Crypt (for clarity and because it is conventional)
paulson
parents:
2264
diff
changeset
|
270 |
\ {|NB, Crypt (shrK A) {|Agent B, Key K, NA|}, X|} \ |
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
271 |
\ : set_of_list evs; \ |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
272 |
\ Says Server A' \ |
2284
80ebd1a213fd
Swapped arguments of Crypt (for clarity and because it is conventional)
paulson
parents:
2264
diff
changeset
|
273 |
\ {|NB', Crypt (shrK A') {|Agent B', Key K, NA'|}, X'|} \ |
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
274 |
\ : set_of_list evs; \ |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
275 |
\ evs : yahalom lost |] \ |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
276 |
\ ==> A=A' & B=B' & NA=NA' & NB=NB'"; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
277 |
by (dtac lemma 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
278 |
by (REPEAT (etac exE 1)); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
279 |
(*Duplicate the assumption*) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
280 |
by (forw_inst_tac [("psi", "ALL C.?P(C)")] asm_rl 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
281 |
by (fast_tac (!claset addSDs [spec]) 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
282 |
qed "unique_session_keys"; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
283 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
284 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
285 |
(** Crucial secrecy property: Spy does not see the keys sent in msg YM3 **) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
286 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
287 |
goal thy |
2155 | 288 |
"!!evs. [| A ~: lost; B ~: lost; A ~= B; \ |
289 |
\ evs : yahalom lost |] \ |
|
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
290 |
\ ==> Says Server A \ |
2284
80ebd1a213fd
Swapped arguments of Crypt (for clarity and because it is conventional)
paulson
parents:
2264
diff
changeset
|
291 |
\ {|NB, Crypt (shrK A) {|Agent B, Key K, NA|}, \ |
80ebd1a213fd
Swapped arguments of Crypt (for clarity and because it is conventional)
paulson
parents:
2264
diff
changeset
|
292 |
\ Crypt (shrK B) {|NB, Key K, Agent A|}|} \ |
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
293 |
\ : set_of_list evs --> \ |
2155 | 294 |
\ Says A Spy {|NA, NB, Key K|} ~: set_of_list evs --> \ |
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
295 |
\ Key K ~: analz (sees lost Spy evs)"; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
296 |
by (etac yahalom.induct 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
297 |
by analz_Fake_tac; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
298 |
by (ALLGOALS |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
299 |
(asm_simp_tac |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
300 |
(!simpset addsimps ([analz_subset_parts RS contra_subsetD, |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
301 |
analz_insert_Key_newK] @ pushes) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
302 |
setloop split_tac [expand_if]))); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
303 |
(*YM3*) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
304 |
by (fast_tac (!claset addIs [parts_insertI] |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
305 |
addEs [Says_imp_old_keys RS less_irrefl] |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
306 |
addss (!simpset)) 2); |
2155 | 307 |
(*OR4, Fake*) |
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
308 |
by (REPEAT_FIRST (resolve_tac [conjI, impI] ORELSE' spy_analz_tac)); |
2155 | 309 |
(*Oops*) |
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
310 |
by (fast_tac (!claset delrules [disjE] |
2170 | 311 |
addDs [unique_session_keys] |
312 |
addss (!simpset)) 1); |
|
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
313 |
val lemma = result() RS mp RS mp RSN(2,rev_notE); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
314 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
315 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
316 |
(*Final version: Server's message in the most abstract form*) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
317 |
goal thy |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
318 |
"!!evs. [| Says Server A \ |
2284
80ebd1a213fd
Swapped arguments of Crypt (for clarity and because it is conventional)
paulson
parents:
2264
diff
changeset
|
319 |
\ {|NB, Crypt (shrK A) {|Agent B, K, NA|}, \ |
80ebd1a213fd
Swapped arguments of Crypt (for clarity and because it is conventional)
paulson
parents:
2264
diff
changeset
|
320 |
\ Crypt (shrK B) {|NB, K, Agent A|}|} \ |
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
321 |
\ : set_of_list evs; \ |
2155 | 322 |
\ Says A Spy {|NA, NB, K|} ~: set_of_list evs; \ |
323 |
\ A ~: lost; B ~: lost; evs : yahalom lost |] \ |
|
324 |
\ ==> K ~: analz (sees lost Spy evs)"; |
|
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
325 |
by (forward_tac [Says_Server_message_form] 1 THEN assume_tac 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
326 |
by (fast_tac (!claset addSEs [lemma]) 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
327 |
qed "Spy_not_see_encrypted_key"; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
328 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
329 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
330 |
goal thy |
2155 | 331 |
"!!evs. [| C ~: {A,B,Server}; \ |
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
332 |
\ Says Server A \ |
2284
80ebd1a213fd
Swapped arguments of Crypt (for clarity and because it is conventional)
paulson
parents:
2264
diff
changeset
|
333 |
\ {|NB, Crypt (shrK A) {|Agent B, K, NA|}, \ |
80ebd1a213fd
Swapped arguments of Crypt (for clarity and because it is conventional)
paulson
parents:
2264
diff
changeset
|
334 |
\ Crypt (shrK B) {|NB, K, Agent A|}|} \ |
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
335 |
\ : set_of_list evs; \ |
2155 | 336 |
\ Says A Spy {|NA, NB, K|} ~: set_of_list evs; \ |
337 |
\ A ~: lost; B ~: lost; evs : yahalom lost |] \ |
|
338 |
\ ==> K ~: analz (sees lost C evs)"; |
|
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
339 |
by (rtac (subset_insertI RS sees_mono RS analz_mono RS contra_subsetD) 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
340 |
by (rtac (sees_lost_agent_subset_sees_Spy RS analz_mono RS contra_subsetD) 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
341 |
by (FIRSTGOAL (rtac Spy_not_see_encrypted_key)); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
342 |
by (REPEAT_FIRST (fast_tac (!claset addIs [yahalom_mono RS subsetD]))); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
343 |
qed "Agent_not_see_encrypted_key"; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
344 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
345 |
|
2155 | 346 |
(*** Security Guarantees for A and B ***) |
347 |
||
348 |
(*If the encrypted message appears then it originated with the Server.*) |
|
349 |
goal thy |
|
2284
80ebd1a213fd
Swapped arguments of Crypt (for clarity and because it is conventional)
paulson
parents:
2264
diff
changeset
|
350 |
"!!evs. [| Crypt (shrK A) {|Agent B, Key K, NA|} \ |
2155 | 351 |
\ : parts (sees lost Spy evs); \ |
352 |
\ A ~: lost; evs : yahalom lost |] \ |
|
353 |
\ ==> EX NB. Says Server A \ |
|
2284
80ebd1a213fd
Swapped arguments of Crypt (for clarity and because it is conventional)
paulson
parents:
2264
diff
changeset
|
354 |
\ {|NB, Crypt (shrK A) {|Agent B, Key K, NA|}, \ |
80ebd1a213fd
Swapped arguments of Crypt (for clarity and because it is conventional)
paulson
parents:
2264
diff
changeset
|
355 |
\ Crypt (shrK B) {|NB, Key K, Agent A|}|} \ |
2155 | 356 |
\ : set_of_list evs"; |
357 |
by (etac rev_mp 1); |
|
358 |
by (parts_induct_tac 1); |
|
359 |
(*The nested conjunctions are entirely useless*) |
|
360 |
by (REPEAT_FIRST (rtac conjI ORELSE' fast_tac (!claset delrules [conjI]))); |
|
361 |
qed "A_trust_YM3"; |
|
362 |
||
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
363 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
364 |
(*B knows, by the first part of A's message, that the Server distributed |
2155 | 365 |
the key for A and B. *) |
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
366 |
goal thy |
2284
80ebd1a213fd
Swapped arguments of Crypt (for clarity and because it is conventional)
paulson
parents:
2264
diff
changeset
|
367 |
"!!evs. [| Crypt (shrK B) {|Nonce NB, Key K, Agent A|} \ |
2155 | 368 |
\ : parts (sees lost Spy evs); \ |
369 |
\ B ~: lost; evs : yahalom lost |] \ |
|
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
370 |
\ ==> EX NA. Says Server A \ |
2155 | 371 |
\ {|Nonce NB, \ |
2284
80ebd1a213fd
Swapped arguments of Crypt (for clarity and because it is conventional)
paulson
parents:
2264
diff
changeset
|
372 |
\ Crypt (shrK A) {|Agent B, Key K, Nonce NA|}, \ |
80ebd1a213fd
Swapped arguments of Crypt (for clarity and because it is conventional)
paulson
parents:
2264
diff
changeset
|
373 |
\ Crypt (shrK B) {|Nonce NB, Key K, Agent A|}|} \ |
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
374 |
\ : set_of_list evs"; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
375 |
by (etac rev_mp 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
376 |
by (parts_induct_tac 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
377 |
(*YM3*) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
378 |
by (Fast_tac 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
379 |
qed "B_trusts_YM4_shrK"; |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
380 |
|
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
381 |
(*With this variant we don't bother to use the 2nd part of YM4 at all, since |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
382 |
Nonce NB is available in the first part. However the 2nd part does assure B |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
383 |
of A's existence.*) |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
384 |
|
2155 | 385 |
(*What can B deduce from receipt of YM4? Stronger and simpler than Yahalom |
386 |
because we do not have to show that NB is secret. *) |
|
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
387 |
goal thy |
2284
80ebd1a213fd
Swapped arguments of Crypt (for clarity and because it is conventional)
paulson
parents:
2264
diff
changeset
|
388 |
"!!evs. [| Says A' B {|Crypt (shrK B) {|Nonce NB, Key K, Agent A|}, \ |
80ebd1a213fd
Swapped arguments of Crypt (for clarity and because it is conventional)
paulson
parents:
2264
diff
changeset
|
389 |
\ Crypt K (Nonce NB)|} : set_of_list evs; \ |
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
390 |
\ A ~: lost; B ~: lost; evs : yahalom lost |] \ |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
391 |
\ ==> EX NA. Says Server A \ |
2155 | 392 |
\ {|Nonce NB, \ |
2284
80ebd1a213fd
Swapped arguments of Crypt (for clarity and because it is conventional)
paulson
parents:
2264
diff
changeset
|
393 |
\ Crypt (shrK A) {|Agent B, Key K, Nonce NA|}, \ |
80ebd1a213fd
Swapped arguments of Crypt (for clarity and because it is conventional)
paulson
parents:
2264
diff
changeset
|
394 |
\ Crypt (shrK B) {|Nonce NB, Key K, Agent A|}|} \ |
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
395 |
\ : set_of_list evs"; |
2170 | 396 |
by (etac (Says_imp_sees_Spy RS parts.Inj RS MPair_parts) 1); |
2111
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
397 |
by (fast_tac (!claset addSDs [B_trusts_YM4_shrK]) 1); |
81c8d46edfa3
New version of Yahalom, as recommended on p 259 of BAN paper
paulson
parents:
diff
changeset
|
398 |
qed "B_trust_YM4"; |