author | paulson |
Thu, 12 Sep 1996 10:40:05 +0200 | |
changeset 1985 | 84cf16192e03 |
child 1995 | c80e58e78d9c |
permissions | -rw-r--r-- |
1985
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
1 |
(* Title: HOL/Auth/OtwayRees |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
2 |
ID: $Id$ |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
3 |
Author: Lawrence C Paulson, Cambridge University Computer Laboratory |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
4 |
Copyright 1996 University of Cambridge |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
5 |
|
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
6 |
Inductive relation "yahalom" for the Yahalom protocol. |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
7 |
|
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
8 |
From page 257 of |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
9 |
Burrows, Abadi and Needham. A Logic of Authentication. |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
10 |
Proc. Royal Soc. 426 (1989) |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
11 |
*) |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
12 |
|
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
13 |
OtwayRees = Shared + |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
14 |
|
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
15 |
consts yahalom :: "event list set" |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
16 |
inductive yahalom |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
17 |
intrs |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
18 |
(*Initial trace is empty*) |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
19 |
Nil "[]: yahalom" |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
20 |
|
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
21 |
(*The enemy MAY say anything he CAN say. We do not expect him to |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
22 |
invent new nonces here, but he can also use NS1. Common to |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
23 |
all similar protocols.*) |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
24 |
Fake "[| evs: yahalom; B ~= Enemy; X: synth (analz (sees Enemy evs)) |] |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
25 |
==> Says Enemy B X # evs : yahalom" |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
26 |
|
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
27 |
(*Alice initiates a protocol run*) |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
28 |
YM1 "[| evs: yahalom; A ~= B |] |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
29 |
==> Says A B {|Nonce (newN evs), Agent A |} # evs : yahalom" |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
30 |
|
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
31 |
(*Bob's response to Alice's message. Bob doesn't know who |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
32 |
the sender is, hence the A' in the sender field. |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
33 |
We modify the published protocol by NOT encrypting NB.*) |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
34 |
YM2 "[| evs: yahalom; B ~= Server; |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
35 |
Says A' B {|Nonce NA, Agent A|} : set_of_list evs |] |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
36 |
==> Says B Server |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
37 |
{|Agent B, |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
38 |
Crypt {|Agent A, Nonce NA, Nonce (newN evs)|} (shrK B)|} |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
39 |
# evs : yahalom" |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
40 |
|
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
41 |
(*The Server receives Bob's message. He responds by sending a |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
42 |
new session key to Alice, with a packet for forwarding to Bob.*) |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
43 |
YM3 "[| evs: yahalom; B ~= Server; |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
44 |
Says B' Server |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
45 |
{|Nonce NA, Agent A, Agent B, |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
46 |
Crypt {|Nonce NA, Agent A, Agent B|} (shrK A), |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
47 |
Nonce NB, |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
48 |
Crypt {|Nonce NA, Agent A, Agent B|} (shrK B)|} |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
49 |
: set_of_list evs |] |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
50 |
==> Says Server B |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
51 |
{|Nonce NA, |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
52 |
Crypt {|Nonce NA, Key (newK evs)|} (shrK A), |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
53 |
Crypt {|Nonce NB, Key (newK evs)|} (shrK B)|} |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
54 |
# evs : yahalom" |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
55 |
|
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
56 |
(*Bob receives the Server's (?) message and compares the Nonces with |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
57 |
those in the message he previously sent the Server.*) |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
58 |
YM4 "[| evs: yahalom; A ~= B; |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
59 |
Says S B {|Nonce NA, X, Crypt {|Nonce NB, Key K|} (shrK B)|} |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
60 |
: set_of_list evs; |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
61 |
Says B Server {|Nonce NA, Agent A, Agent B, X', Nonce NB, X''|} |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
62 |
: set_of_list evs |] |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
63 |
==> (Says B A {|Nonce NA, X|}) # evs : yahalom" |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
64 |
|
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
65 |
(*Alice checks her Nonce, then sends a dummy message to Bob, |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
66 |
using the new session key.*) |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
67 |
YM5 "[| evs: yahalom; |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
68 |
Says B' A {|Nonce NA, Crypt {|Nonce NA, Key K|} (shrK A)|} |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
69 |
: set_of_list evs; |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
70 |
Says A B {|Nonce NA, Agent A, Agent B, X|} : set_of_list evs |] |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
71 |
==> Says A B (Crypt (Agent A) K) # evs : yahalom" |
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
72 |
|
84cf16192e03
Tidied many proofs, using AddIffs to let equivalences take
paulson
parents:
diff
changeset
|
73 |
end |