src/HOL/Auth/TLS.ML
author paulson
Fri, 19 Sep 1997 18:27:31 +0200
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child 3687 fb7d096d7884
permissions -rw-r--r--
First working version with Oops event for session keys
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(*  Title:      HOL/Auth/TLS
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    ID:         $Id$
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    Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
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    Copyright   1997  University of Cambridge
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Protocol goals: 
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* M, serverK(NA,NB,M) and clientK(NA,NB,M) will be known only to the two
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     parties (though A is not necessarily authenticated).
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* B upon receiving CertVerify knows that A is present (But this
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    message is optional!)
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* A upon receiving ServerFinished knows that B is present
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* Each party who has received a FINISHED message can trust that the other
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  party agrees on all message components, including XA and XB (thus foiling
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  rollback attacks).
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*)
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open TLS;
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proof_timing:=true;
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HOL_quantifiers := false;
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(** We mostly DO NOT unfold the definition of "certificate".  The attached
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    lemmas unfold it lazily, when "certificate B KB" occurs in appropriate
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    contexts.
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**)
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goalw thy [certificate_def] 
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    "parts (insert (certificate B KB) H) =  \
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\    parts (insert (Crypt (priK Server) {|Agent B, Key KB|}) H)";
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by (rtac refl 1);
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qed "parts_insert_certificate";
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goalw thy [certificate_def] 
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    "analz (insert (certificate B KB) H) =  \
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\    analz (insert (Crypt (priK Server) {|Agent B, Key KB|}) H)";
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by (rtac refl 1);
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qed "analz_insert_certificate";
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Addsimps [parts_insert_certificate, analz_insert_certificate];
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goalw thy [certificate_def] 
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    "(X = certificate B KB) = (Crypt (priK Server) {|Agent B, Key KB|} = X)";
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by (Blast_tac 1);
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qed "eq_certificate_iff";
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AddIffs [eq_certificate_iff];
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(*Injectiveness of key-generating functions*)
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AddIffs [inj_PRF RS inj_eq, inj_sessionK RS inj_eq];
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(* invKey(sessionK x) = sessionK x*)
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Addsimps [isSym_sessionK, rewrite_rule [isSymKey_def] isSym_sessionK];
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(*** clientK and serverK make symmetric keys; no clashes with pubK or priK ***)
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goal thy "pubK A ~= sessionK arg";
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br notI 1;
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by (dres_inst_tac [("f","isSymKey")] arg_cong 1);
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by (Full_simp_tac 1);
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qed "pubK_neq_sessionK";
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goal thy "priK A ~= sessionK arg";
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br notI 1;
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by (dres_inst_tac [("f","isSymKey")] arg_cong 1);
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by (Full_simp_tac 1);
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qed "priK_neq_sessionK";
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val keys_distinct = [pubK_neq_sessionK, priK_neq_sessionK];
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AddIffs (keys_distinct @ (keys_distinct RL [not_sym]));
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(**** Protocol Proofs ****)
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(*A "possibility property": there are traces that reach the end.
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  This protocol has three end points and six messages to consider.*)
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(** These proofs make the further assumption that the Nonce_supply nonces 
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	(which have the form  @ N. Nonce N ~: used evs)
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    lie outside the range of PRF.  This assumption seems reasonable, but
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    as it is needed only for the possibility theorems, it is not taken
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    as an axiom.
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**)
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(*Possibility property ending with ClientAccepts.*)
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goal thy 
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 "!!A B. [| ALL evs. (@ N. Nonce N ~: used evs) ~: range PRF;  \
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\           A ~= B |] ==> EX SID M. EX evs: tls.    \
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\  Notes A {|Number SID, Agent A, Agent B, Nonce M|} : set evs";
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by (REPEAT (resolve_tac [exI,bexI] 1));
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by (rtac (tls.Nil RS tls.ClientHello RS tls.ServerHello RS tls.ClientCertKeyEx
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	RS tls.ClientFinished RS tls.ServerFinished RS tls.ClientAccepts) 2);
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by possibility_tac;
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by (REPEAT (Blast_tac 1));
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result();
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(*And one for ServerAccepts.  Either FINISHED message may come first.*)
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goal thy 
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 "!!A B. [| ALL evs. (@ N. Nonce N ~: used evs) ~: range PRF;  \
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\           A ~= B |] ==> EX SID NA XA NB XB M. EX evs: tls.    \
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\  Notes B {|Number SID, Agent A, Agent B, Nonce M|} : set evs";
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by (REPEAT (resolve_tac [exI,bexI] 1));
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by (rtac (tls.Nil RS tls.ClientHello RS tls.ServerHello RS tls.ClientCertKeyEx
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	  RS tls.ServerFinished RS tls.ClientFinished RS tls.ServerAccepts) 2);
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by possibility_tac;
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by (REPEAT (Blast_tac 1));
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result();
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(*Another one, for CertVerify (which is optional)*)
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goal thy 
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 "!!A B. [| ALL evs. (@ N. Nonce N ~: used evs) ~: range PRF;  \
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\           A ~= B |] ==> EX NB PMS. EX evs: tls.   \
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\  Says A B (Crypt (priK A)                 \
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\            (Hash{|Nonce NB, certificate B (pubK B), Nonce PMS|})) : set evs";
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by (REPEAT (resolve_tac [exI,bexI] 1));
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by (rtac (tls.Nil RS tls.ClientHello RS tls.ServerHello RS tls.ClientCertKeyEx
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	  RS tls.CertVerify) 2);
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by possibility_tac;
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by (REPEAT (Blast_tac 1));
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result();
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(*Another one, for session resumption (both ServerResume and ClientResume) *)
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goal thy 
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 "!!A B. [| evs0 : tls;     \
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\           Notes A {|Number SID, Agent A, Agent B, Nonce M|} : set evs0; \
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\           Notes B {|Number SID, Agent A, Agent B, Nonce M|} : set evs0; \
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\           ALL evs. (@ N. Nonce N ~: used evs) ~: range PRF;  \
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\           A ~= B |] ==> EX NA XA NB XB. EX evs: tls.    \
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\  Says A B (Crypt (clientK(NA,NB,M))                           \
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\            (Hash{|Nonce M, Number SID,             \
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\                   Nonce NA, Number XA, Agent A,      \
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\                   Nonce NB, Number XB, Agent B|})) : set evs";
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by (REPEAT (resolve_tac [exI,bexI] 1));
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by (etac (tls.ClientHello RS tls.ServerResume RS tls.ClientResume) 2);
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by possibility_tac;
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by (REPEAT (Blast_tac 1));
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result();
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(**** Inductive proofs about tls ****)
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(*Nobody sends themselves messages*)
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goal thy "!!evs. evs : tls ==> ALL A X. Says A A X ~: set evs";
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by (etac tls.induct 1);
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by (Auto_tac());
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qed_spec_mp "not_Says_to_self";
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Addsimps [not_Says_to_self];
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AddSEs   [not_Says_to_self RSN (2, rev_notE)];
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(*Induction for regularity theorems.  If induction formula has the form
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   X ~: analz (spies evs) --> ... then it shortens the proof by discarding
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   needless information about analz (insert X (spies evs))  *)
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fun parts_induct_tac i = 
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    etac tls.induct i
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    THEN 
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    REPEAT (FIRSTGOAL analz_mono_contra_tac)
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    THEN 
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    fast_tac (!claset addss (!simpset)) i THEN
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    ALLGOALS (asm_full_simp_tac (!simpset setloop split_tac [expand_if]));
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(** Theorems of the form X ~: parts (spies evs) imply that NOBODY
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    sends messages containing X! **)
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(*Spy never sees another agent's private key! (unless it's bad at start)*)
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goal thy 
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 "!!evs. evs : tls ==> (Key (priK A) : parts (spies evs)) = (A : bad)";
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by (parts_induct_tac 1);
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by (Fake_parts_insert_tac 1);
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qed "Spy_see_priK";
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Addsimps [Spy_see_priK];
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goal thy 
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 "!!evs. evs : tls ==> (Key (priK A) : analz (spies evs)) = (A : bad)";
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by (auto_tac(!claset addDs [impOfSubs analz_subset_parts], !simpset));
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qed "Spy_analz_priK";
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Addsimps [Spy_analz_priK];
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goal thy  "!!A. [| Key (priK A) : parts (spies evs);       \
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\                  evs : tls |] ==> A:bad";
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by (blast_tac (!claset addDs [Spy_see_priK]) 1);
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qed "Spy_see_priK_D";
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bind_thm ("Spy_analz_priK_D", analz_subset_parts RS subsetD RS Spy_see_priK_D);
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AddSDs [Spy_see_priK_D, Spy_analz_priK_D];
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(*This lemma says that no false certificates exist.  One might extend the
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  model to include bogus certificates for the agents, but there seems
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  little point in doing so: the loss of their private keys is a worse
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  breach of security.*)
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goalw thy [certificate_def]
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 "!!evs. evs : tls     \
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\        ==> certificate B KB : parts (spies evs) --> KB = pubK B";
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by (parts_induct_tac 1);
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by (Fake_parts_insert_tac 1);
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bind_thm ("Server_cert_pubB", result() RSN (2, rev_mp));
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(*Replace key KB in ClientCertKeyEx by (pubK B) *)
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val ClientCertKeyEx_tac = 
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    forward_tac [Says_imp_spies RS parts.Inj RS 
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		 parts.Snd RS parts.Snd RS parts.Snd RS Server_cert_pubB]
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    THEN' assume_tac
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    THEN' hyp_subst_tac;
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fun analz_induct_tac i = 
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    etac tls.induct i   THEN
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    ClientCertKeyEx_tac  (i+7)  THEN	(*ClientFinished*)
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    ClientCertKeyEx_tac  (i+6)  THEN	(*CertVerify*)
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    ClientCertKeyEx_tac  (i+5)  THEN	(*ClientCertKeyEx*)
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    ALLGOALS (asm_simp_tac 
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              (!simpset addcongs [if_weak_cong]
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                        setloop split_tac [expand_if]))  THEN
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    (*Remove instances of pubK B:  the Spy already knows all public keys.
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      Combining the two simplifier calls makes them run extremely slowly.*)
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    ALLGOALS (asm_simp_tac 
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              (!simpset addcongs [if_weak_cong]
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			addsimps [insert_absorb]
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                        setloop split_tac [expand_if]));
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(*** Notes are made under controlled circumstances ***)
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goal thy "!!evs. [| Notes A {|Agent B, X|} : set evs;  evs : tls |]  \
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\                ==> Crypt (pubK B) X : parts (spies evs)";
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by (etac rev_mp 1);
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by (analz_induct_tac 1);
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by (blast_tac (!claset addIs [parts_insertI]) 1);
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qed "Notes_Crypt_parts_spies";
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(*C might be either A or B*)
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goal thy
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    "!!evs. [| Notes C {|Number SID, Agent A, Agent B, Nonce M|} : set evs;  \
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\              evs : tls     \
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\           |] ==> M : range PRF";
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by (etac rev_mp 1);
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by (parts_induct_tac 1);
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by (Auto_tac());
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qed "Notes_master_range_PRF";
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(*C might be either A or B*)
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goal thy
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 "!!evs. [| Notes C {|Number SID, Agent A, Agent B, Nonce(PRF(PMS,NA,NB))|} \
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\             : set evs;     evs : tls     \
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\        |] ==> Crypt (pubK B) (Nonce PMS) : parts (spies evs)";
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by (etac rev_mp 1);
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by (parts_induct_tac 1);
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(*Fake*)
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by (blast_tac (!claset addIs [parts_insertI]) 1);
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(*Client, Server Accept*)
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by (Step_tac 1);
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by (REPEAT (blast_tac (!claset addSEs spies_partsEs
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                               addSDs [Notes_Crypt_parts_spies]) 1));
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qed "Notes_master_imp_Crypt_PMS";
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(*Compared with the theorem above, both premise and conclusion are stronger*)
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goal thy
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 "!!evs. [| Notes A {|Number SID, Agent A, Agent B, Nonce(PRF(PMS,NA,NB))|} \
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\             : set evs;     evs : tls     \
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\        |] ==> Notes A {|Agent B, Nonce PMS|} : set evs";
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by (etac rev_mp 1);
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by (parts_induct_tac 1);
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(*ServerAccepts*)
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by (Fast_tac 1);	(*Blast_tac's very slow here*)
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qed "Notes_master_imp_Notes_PMS";
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(*Every Nonce that's hashed is already in past traffic; this event
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  occurs in CertVerify.  The condition NB ~: range PRF excludes the 
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  MASTER SECRET from consideration; it is created using PRF.*)
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goal thy "!!evs. [| Hash {|Nonce NB, X|} : parts (spies evs);  \
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\                   NB ~: range PRF;  evs : tls |]  \
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\                ==> Nonce NB : parts (spies evs)";
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by (etac rev_mp 1);
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by (etac rev_mp 1);
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by (parts_induct_tac 1);
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   284
by (ALLGOALS (asm_simp_tac (!simpset addsimps [parts_insert_spies])));
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paulson
parents: 3683
diff changeset
   285
(*Server/Client Resume: wrong sort of nonce!*)
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   286
by (REPEAT (blast_tac (!claset addSDs [Notes_master_range_PRF]) 5));
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   287
(*FINISHED messages are trivial because M : range PRF*)
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   288
by (REPEAT (Blast_tac 3));
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   289
(*CertVerify is the only interesting case*)
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   290
by (blast_tac (!claset addSEs spies_partsEs) 2);
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   291
by (Fake_parts_insert_tac 1);
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   292
qed "Hash_Nonce_CV";
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   293
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   294
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   295
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   296
(*** Protocol goal: if B receives CertVerify, then A sent it ***)
3474
44249bba00ec Baby TLS. Proofs work, but model seems unrealistic
paulson
parents:
diff changeset
   297
3506
a36e0a49d2cd New proofs involving CERTIFICATE VERIFY
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parents: 3500
diff changeset
   298
(*B can check A's signature if he has received A's certificate.
a36e0a49d2cd New proofs involving CERTIFICATE VERIFY
paulson
parents: 3500
diff changeset
   299
  Perhaps B~=Spy is unnecessary, but there's no obvious proof if the first
3480
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   300
  message is Fake.  We don't need guarantees for the Spy anyway.  We must
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   301
  assume A~:bad; otherwise, the Spy can forge A's signature.*)
3519
ab0a9fbed4c0 Changing "lost" from a parameter of protocol definitions to a constant.
paulson
parents: 3515
diff changeset
   302
goal thy
3506
a36e0a49d2cd New proofs involving CERTIFICATE VERIFY
paulson
parents: 3500
diff changeset
   303
 "!!evs. [| X = Crypt (priK A)                                        \
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   304
\                 (Hash{|Nonce NB, certificate B KB, Nonce PMS|});      \
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   305
\           evs : tls;  A ~: bad;  B ~= Spy |]                       \
3676
cbaec955056b Addition of SessionIDs to the Hello and Finished messages
paulson
parents: 3672
diff changeset
   306
\    ==> Says B A {|Nonce NB, Number SID, Number XB, certificate B KB|}  \
3506
a36e0a49d2cd New proofs involving CERTIFICATE VERIFY
paulson
parents: 3500
diff changeset
   307
\          : set evs --> \
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   308
\        X : parts (spies evs) --> Says A B X : set evs";
3480
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   309
by (hyp_subst_tac 1);
3519
ab0a9fbed4c0 Changing "lost" from a parameter of protocol definitions to a constant.
paulson
parents: 3515
diff changeset
   310
by (parts_induct_tac 1);
3474
44249bba00ec Baby TLS. Proofs work, but model seems unrealistic
paulson
parents:
diff changeset
   311
by (Fake_parts_insert_tac 1);
3480
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   312
(*ServerHello: nonce NB cannot be in X because it's fresh!*)
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   313
by (blast_tac (!claset addSDs [Hash_Nonce_CV]
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   314
	               addSEs spies_partsEs) 1);
3474
44249bba00ec Baby TLS. Proofs work, but model seems unrealistic
paulson
parents:
diff changeset
   315
qed_spec_mp "TrustCertVerify";
44249bba00ec Baby TLS. Proofs work, but model seems unrealistic
paulson
parents:
diff changeset
   316
44249bba00ec Baby TLS. Proofs work, but model seems unrealistic
paulson
parents:
diff changeset
   317
3685
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   318
(*If CertVerify is present then A has chosen PMS.*)
3506
a36e0a49d2cd New proofs involving CERTIFICATE VERIFY
paulson
parents: 3500
diff changeset
   319
goal thy
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   320
 "!!evs. [| Crypt (priK A) (Hash{|Nonce NB, certificate B KB, Nonce PMS|})  \
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   321
\             : parts (spies evs);                                \
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   322
\           evs : tls;  A ~: bad |]                                      \
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   323
\        ==> Notes A {|Agent B, Nonce PMS|} : set evs";
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   324
be rev_mp 1;
3519
ab0a9fbed4c0 Changing "lost" from a parameter of protocol definitions to a constant.
paulson
parents: 3515
diff changeset
   325
by (parts_induct_tac 1);
ab0a9fbed4c0 Changing "lost" from a parameter of protocol definitions to a constant.
paulson
parents: 3515
diff changeset
   326
by (Fake_parts_insert_tac 1);
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   327
qed "UseCertVerify";
3474
44249bba00ec Baby TLS. Proofs work, but model seems unrealistic
paulson
parents:
diff changeset
   328
3480
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   329
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   330
(*No collection of keys can help the spy get new private keys*)
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   331
goal thy  
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   332
 "!!evs. evs : tls ==>                                    \
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   333
\  ALL KK. (Key(priK B) : analz (Key``KK Un (spies evs))) =  \
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   334
\            (priK B : KK | B : bad)";
3480
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   335
by (etac tls.induct 1);
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   336
by (ALLGOALS
3519
ab0a9fbed4c0 Changing "lost" from a parameter of protocol definitions to a constant.
paulson
parents: 3515
diff changeset
   337
    (asm_simp_tac (analz_image_keys_ss
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   338
		   addsimps (analz_insert_certificate::keys_distinct))));
3480
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   339
(*Fake*) 
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   340
by (spy_analz_tac 2);
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   341
(*Base*)
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   342
by (Blast_tac 1);
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   343
qed_spec_mp "analz_image_priK";
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   344
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   345
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   346
(*Lemma for the trivial direction of the if-and-only-if*)
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   347
goal thy  
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   348
 "!!evs. (X : analz (G Un H)) --> (X : analz H)  ==> \
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   349
\        (X : analz (G Un H))  =  (X : analz H)";
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   350
by (blast_tac (!claset addIs [impOfSubs analz_mono]) 1);
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   351
val lemma = result();
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   352
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   353
(*slightly speeds up the big simplification below*)
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   354
goal thy "!!evs. KK <= range sessionK ==> priK B ~: KK";
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   355
by (Blast_tac 1);
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   356
val range_sessionkeys_not_priK = result();
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   357
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   358
(*Knowing some session keys is no help in getting new nonces*)
3480
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   359
goal thy  
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   360
 "!!evs. evs : tls ==>                                 \
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   361
\    ALL KK. KK <= range sessionK -->           \
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   362
\            (Nonce N : analz (Key``KK Un (spies evs))) = \
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   363
\            (Nonce N : analz (spies evs))";
3480
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   364
by (etac tls.induct 1);
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   365
by (ClientCertKeyEx_tac 6);
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   366
by (REPEAT_FIRST (resolve_tac [allI, impI]));
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   367
by (REPEAT_FIRST (rtac lemma));
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   368
writeln"SLOW simplification: 55 secs??";
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   369
(*ClientCertKeyEx is to blame, causing case splits for A, B: bad*)
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   370
by (ALLGOALS
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   371
    (asm_simp_tac (analz_image_keys_ss 
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   372
		   addsimps [range_sessionkeys_not_priK, 
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   373
			     analz_image_priK, analz_insert_certificate])));
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   374
by (ALLGOALS (asm_simp_tac (!simpset addsimps [insert_absorb])));
3480
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   375
(*Fake*) 
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   376
by (spy_analz_tac 2);
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   377
(*Base*)
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   378
by (Blast_tac 1);
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   379
qed_spec_mp "analz_image_keys";
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   380
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   381
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   382
goal thy "!!evs. evs : tls ==> Notes A {|Agent B, Nonce (PRF x)|} ~: set evs";
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   383
by (parts_induct_tac 1);
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   384
(*ClientCertKeyEx: PMS is assumed to differ from any PRF.*)
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   385
by (Blast_tac 1);
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   386
qed "no_Notes_A_PRF";
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   387
Addsimps [no_Notes_A_PRF];
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   388
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   389
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   390
goal thy "!!evs. [| Nonce (PRF (PMS,NA,NB)) : parts (spies evs);  \
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   391
\                   evs : tls |]  \
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   392
\                ==> Nonce PMS : parts (spies evs)";
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   393
by (etac rev_mp 1);
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   394
by (parts_induct_tac 1);
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   395
by (ALLGOALS (asm_simp_tac (!simpset addsimps [parts_insert_spies])));
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   396
by (Fake_parts_insert_tac 1);
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   397
(*Six others, all trivial or by freshness*)
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   398
by (REPEAT (blast_tac (!claset addSDs [Notes_Crypt_parts_spies]
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   399
                               addSEs spies_partsEs) 1));
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   400
qed "MS_imp_PMS";
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   401
AddSDs [MS_imp_PMS];
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   402
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   403
3474
44249bba00ec Baby TLS. Proofs work, but model seems unrealistic
paulson
parents:
diff changeset
   404
44249bba00ec Baby TLS. Proofs work, but model seems unrealistic
paulson
parents:
diff changeset
   405
(*** Protocol goal: serverK(NA,NB,M) and clientK(NA,NB,M) remain secure ***)
44249bba00ec Baby TLS. Proofs work, but model seems unrealistic
paulson
parents:
diff changeset
   406
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   407
(** Some lemmas about session keys, comprising clientK and serverK **)
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   408
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   409
(*Lemma: those write keys are never sent if M (MASTER SECRET) is secure.  
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   410
  Converse doesn't hold; betraying M doesn't force the keys to be sent!*)
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   411
3474
44249bba00ec Baby TLS. Proofs work, but model seems unrealistic
paulson
parents:
diff changeset
   412
goal thy 
3686
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   413
 "!!evs. [| ALL A. Says A Spy (Key (sessionK((NA,NB,M),b))) ~: set evs; \
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   414
\           Nonce M ~: analz (spies evs);  evs : tls |]   \
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   415
\        ==> Key (sessionK((NA,NB,M),b)) ~: parts (spies evs)";
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   416
by (etac rev_mp 1);
3480
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   417
by (etac rev_mp 1);
3686
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   418
by (analz_induct_tac 1);	(*30 seconds??*)
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   419
(*Oops*)
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   420
by (asm_simp_tac (analz_image_keys_ss addsimps [analz_image_keys]) 4);
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   421
by (Blast_tac 4);
3480
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   422
(*SpyKeys*)
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   423
by (asm_simp_tac (analz_image_keys_ss addsimps [analz_image_keys]) 3);
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   424
by (blast_tac (!claset addDs [Says_imp_spies RS analz.Inj]) 3);
3480
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   425
(*Fake*) 
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   426
by (spy_analz_tac 2);
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   427
(*Base*)
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   428
by (Blast_tac 1);
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   429
qed "sessionK_notin_parts";
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   430
bind_thm ("sessionK_in_partsE", sessionK_notin_parts RSN (2, rev_notE));
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   431
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   432
Addsimps [sessionK_notin_parts];
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   433
AddSEs [sessionK_in_partsE, 
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   434
	impOfSubs analz_subset_parts RS sessionK_in_partsE];
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   435
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   436
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   437
(*Lemma: session keys are never used if PMS is fresh.  
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   438
  Nonces don't have to agree, allowing session resumption.
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   439
  Converse doesn't hold; revealing PMS doesn't force the keys to be sent.
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   440
  They are NOT suitable as safe elim rules.*)
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   441
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   442
goal thy 
3686
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   443
 "!!evs. [| ALL A. Says A Spy (Key (sessionK((Na, Nb, PRF(PMS,NA,NB)),b))) \
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   444
\                    ~: set evs; \
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   445
\           Nonce PMS ~: parts (spies evs);  evs : tls |]             \
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   446
\  ==> Crypt (sessionK((Na, Nb, PRF(PMS,NA,NB)), b)) Y ~: parts (spies evs)";
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   447
by (etac rev_mp 1);
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   448
by (etac rev_mp 1);
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   449
by (analz_induct_tac 1);
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   450
(*Fake*)
3686
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   451
by (asm_simp_tac (!simpset addsimps [all_conj_distrib, parts_insert_spies]) 2);
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   452
by (Fake_parts_insert_tac 2);
3685
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   453
(*Base, ClientFinished, ServerFinished, ClientResume: 
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   454
  trivial, e.g. by freshness*)
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   455
by (REPEAT 
3685
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   456
    (blast_tac (!claset addSDs [Notes_Crypt_parts_spies, 
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   457
				Notes_master_imp_Crypt_PMS]
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   458
                        addSEs spies_partsEs) 1));
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   459
qed "Crypt_sessionK_notin_parts";
3686
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   460
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   461
Addsimps [Crypt_sessionK_notin_parts];
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   462
AddEs [Crypt_sessionK_notin_parts RSN (2, rev_notE)];
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   463
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   464
3519
ab0a9fbed4c0 Changing "lost" from a parameter of protocol definitions to a constant.
paulson
parents: 3515
diff changeset
   465
(*NEEDED??*)
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   466
goal thy
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   467
 "!!evs. [| Says A B {|certA, Crypt KB (Nonce M)|} : set evs;   \
3519
ab0a9fbed4c0 Changing "lost" from a parameter of protocol definitions to a constant.
paulson
parents: 3515
diff changeset
   468
\           A ~= Spy;  evs : tls |] ==> KB = pubK B";
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   469
be rev_mp 1;
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   470
by (analz_induct_tac 1);
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   471
qed "A_Crypt_pubB";
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   472
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   473
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   474
(*** Unicity results for PMS, the pre-master-secret ***)
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   475
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   476
(*PMS determines B.  Proof borrowed from NS_Public/unique_NA and from Yahalom*)
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   477
goal thy 
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   478
 "!!evs. [| Nonce PMS ~: analz (spies evs);  evs : tls |]   \
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   479
\        ==> EX B'. ALL B.   \
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   480
\              Crypt (pubK B) (Nonce PMS) : parts (spies evs) --> B=B'";
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   481
by (etac rev_mp 1);
3519
ab0a9fbed4c0 Changing "lost" from a parameter of protocol definitions to a constant.
paulson
parents: 3515
diff changeset
   482
by (parts_induct_tac 1);
ab0a9fbed4c0 Changing "lost" from a parameter of protocol definitions to a constant.
paulson
parents: 3515
diff changeset
   483
by (Fake_parts_insert_tac 1);
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   484
(*ClientCertKeyEx*)
3519
ab0a9fbed4c0 Changing "lost" from a parameter of protocol definitions to a constant.
paulson
parents: 3515
diff changeset
   485
by (ClientCertKeyEx_tac 1);
ab0a9fbed4c0 Changing "lost" from a parameter of protocol definitions to a constant.
paulson
parents: 3515
diff changeset
   486
by (asm_simp_tac (!simpset addsimps [all_conj_distrib]) 1);
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   487
by (expand_case_tac "PMS = ?y" 1 THEN
3519
ab0a9fbed4c0 Changing "lost" from a parameter of protocol definitions to a constant.
paulson
parents: 3515
diff changeset
   488
    blast_tac (!claset addSEs partsEs) 1);
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   489
val lemma = result();
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   490
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   491
goal thy 
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   492
 "!!evs. [| Crypt(pubK B)  (Nonce PMS) : parts (spies evs); \
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   493
\           Crypt(pubK B') (Nonce PMS) : parts (spies evs); \
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   494
\           Nonce PMS ~: analz (spies evs);                 \
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   495
\           evs : tls |]                                          \
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   496
\        ==> B=B'";
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   497
by (prove_unique_tac lemma 1);
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   498
qed "unique_PMS";
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   499
3685
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   500
(** It is frustrating that we need two versions of the unicity results.
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   501
    But Notes A {|Agent B, Nonce PMS|} determines both A and B, while
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   502
    Crypt(pubK B) (Nonce PMS) determines only B, and sometimes only
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   503
    this weaker item is available.
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   504
**)
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   505
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   506
(*In A's internal Note, PMS determines A and B.*)
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   507
goal thy 
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   508
 "!!evs. [| Nonce PMS ~: analz (spies evs);  evs : tls |]            \
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   509
\ ==> EX A' B'. ALL A B.                                                   \
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   510
\        Notes A {|Agent B, Nonce PMS|} : set evs --> A=A' & B=B'";
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   511
by (etac rev_mp 1);
3519
ab0a9fbed4c0 Changing "lost" from a parameter of protocol definitions to a constant.
paulson
parents: 3515
diff changeset
   512
by (parts_induct_tac 1);
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   513
by (asm_simp_tac (!simpset addsimps [all_conj_distrib]) 1);
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   514
(*ClientCertKeyEx: if PMS is fresh, then it can't appear in Notes A X.*)
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   515
by (expand_case_tac "PMS = ?y" 1 THEN
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   516
    blast_tac (!claset addSDs [Notes_Crypt_parts_spies] addSEs partsEs) 1);
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   517
val lemma = result();
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   518
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   519
goal thy 
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   520
 "!!evs. [| Notes A  {|Agent B,  Nonce PMS|} : set evs;  \
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   521
\           Notes A' {|Agent B', Nonce PMS|} : set evs;  \
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   522
\           Nonce PMS ~: analz (spies evs);      \
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   523
\           evs : tls |]                               \
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   524
\        ==> A=A' & B=B'";
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   525
by (prove_unique_tac lemma 1);
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   526
qed "Notes_unique_PMS";
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   527
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   528
3474
44249bba00ec Baby TLS. Proofs work, but model seems unrealistic
paulson
parents:
diff changeset
   529
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   530
(*If A sends ClientCertKeyEx to an honest B, then the PMS will stay secret.*)
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   531
goal thy
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   532
 "!!evs. [| evs : tls;  A ~: bad;  B ~: bad |]           \
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   533
\        ==> Notes A {|Agent B, Nonce PMS|} : set evs  -->   \
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   534
\            Nonce PMS ~: analz (spies evs)";
3685
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   535
by (analz_induct_tac 1);   (*30 seconds??*)
3686
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   536
(*oops*)
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   537
by (asm_simp_tac (analz_image_keys_ss addsimps [analz_image_keys]) 9);
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   538
(*ClientAccepts and ServerAccepts: because PMS ~: range PRF*)
3686
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   539
by (EVERY (map (fast_tac (!claset addss (!simpset))) [7,6]));
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   540
(*ServerHello, ClientCertKeyEx, ServerResume: mostly freshness reasoning*)
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   541
by (REPEAT (blast_tac (!claset addSEs partsEs
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   542
			       addDs  [Notes_Crypt_parts_spies,
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   543
				       impOfSubs analz_subset_parts,
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   544
				       Says_imp_spies RS analz.Inj]) 4));
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   545
(*ClientHello*)
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   546
by (blast_tac (!claset addSDs [Notes_Crypt_parts_spies]
3686
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   547
                       addSEs spies_partsEs) 3);
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   548
(*SpyKeys*)
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   549
by (asm_simp_tac (analz_image_keys_ss addsimps [analz_image_keys]) 2);
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   550
by (fast_tac (!claset addss (!simpset)) 2);
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   551
(*Fake*)
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   552
by (spy_analz_tac 1);
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   553
bind_thm ("Spy_not_see_PMS", result() RSN (2, rev_mp));
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   554
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   555
3685
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   556
(*Another way of showing unicity*)
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   557
goal thy 
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   558
 "!!evs. [| Notes A  {|Agent B,  Nonce PMS|} : set evs;  \
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   559
\           Notes A' {|Agent B', Nonce PMS|} : set evs;  \
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   560
\           A ~: bad;  B ~: bad;                         \
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   561
\           evs : tls |]                                 \
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   562
\        ==> A=A' & B=B'";
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   563
by (REPEAT (ares_tac [Notes_unique_PMS, Spy_not_see_PMS] 1));
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   564
qed "good_Notes_unique_PMS";
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   565
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   566
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   567
(*If A sends ClientCertKeyEx to an honest B, then the MASTER SECRET
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   568
  will stay secret.*)
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   569
goal thy
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   570
 "!!evs. [| evs : tls;  A ~: bad;  B ~: bad |]           \
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   571
\        ==> Notes A {|Agent B, Nonce PMS|} : set evs  -->   \
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   572
\            Nonce (PRF(PMS,NA,NB)) ~: analz (spies evs)";
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   573
by (analz_induct_tac 1);   (*35 seconds*)
3686
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   574
(*Oops*)
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   575
by (asm_simp_tac (analz_image_keys_ss addsimps [analz_image_keys]) 9);
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   576
(*ClientAccepts and ServerAccepts: because PMS was already visible*)
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   577
by (REPEAT (blast_tac (!claset addDs [Spy_not_see_PMS, 
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   578
				      Says_imp_spies RS analz.Inj,
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   579
				      Notes_imp_spies RS analz.Inj]) 6));
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   580
(*ClientHello*)
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   581
by (Blast_tac 3);
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   582
(*SpyKeys: by secrecy of the PMS, Spy cannot make the MS*)
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   583
by (asm_simp_tac (analz_image_keys_ss addsimps [analz_image_keys]) 2);
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   584
by (blast_tac (!claset addSDs [Spy_not_see_PMS, 
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   585
			       Says_imp_spies RS analz.Inj]) 2);
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   586
(*Fake*)
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   587
by (spy_analz_tac 1);
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   588
(*ServerHello and ClientCertKeyEx: mostly freshness reasoning*)
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   589
by (REPEAT (blast_tac (!claset addSEs partsEs
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   590
			       addDs  [Notes_Crypt_parts_spies,
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   591
				       impOfSubs analz_subset_parts,
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   592
				       Says_imp_spies RS analz.Inj]) 1));
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   593
bind_thm ("Spy_not_see_MS", result() RSN (2, rev_mp));
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   594
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   595
3685
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   596
(*** Protocol goals: if A receives ServerFinished, then B is present 
3474
44249bba00ec Baby TLS. Proofs work, but model seems unrealistic
paulson
parents:
diff changeset
   597
     and has used the quoted values XA, XB, etc.  Note that it is up to A
44249bba00ec Baby TLS. Proofs work, but model seems unrealistic
paulson
parents:
diff changeset
   598
     to compare XA with what she originally sent.
44249bba00ec Baby TLS. Proofs work, but model seems unrealistic
paulson
parents:
diff changeset
   599
***)
44249bba00ec Baby TLS. Proofs work, but model seems unrealistic
paulson
parents:
diff changeset
   600
3685
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   601
(*The mention of her name (A) in X assures A that B knows who she is.*)
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   602
goal thy
3686
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   603
 "!!evs. [| ALL A. Says A Spy (Key (serverK(Na,Nb,M))) ~: set evs; \
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   604
\           X = Crypt (serverK(Na,Nb,M))                  \
3676
cbaec955056b Addition of SessionIDs to the Hello and Finished messages
paulson
parents: 3672
diff changeset
   605
\                 (Hash{|Nonce M, Number SID,             \
cbaec955056b Addition of SessionIDs to the Hello and Finished messages
paulson
parents: 3672
diff changeset
   606
\                        Nonce NA, Number XA, Agent A,    \
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   607
\                        Nonce NB, Number XB, Agent B|}); \
3676
cbaec955056b Addition of SessionIDs to the Hello and Finished messages
paulson
parents: 3672
diff changeset
   608
\           M = PRF(PMS,NA,NB);                           \
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   609
\           evs : tls;  A ~: bad;  B ~: bad |]          \
3676
cbaec955056b Addition of SessionIDs to the Hello and Finished messages
paulson
parents: 3672
diff changeset
   610
\        ==> Notes A {|Agent B, Nonce PMS|} : set evs --> \
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   611
\        X : parts (spies evs) --> Says B A X : set evs";
3686
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   612
by (etac rev_mp 1);
3480
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   613
by (hyp_subst_tac 1);
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   614
by (analz_induct_tac 1);	(*16 seconds*)
3685
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   615
(*ServerResume is trivial, but Blast_tac is too slow*)
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   616
by (Best_tac 3);
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   617
(*ClientCertKeyEx*)
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   618
by (Blast_tac 2);
3480
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   619
(*Fake: the Spy doesn't have the critical session key!*)
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   620
by (REPEAT (rtac impI 1));
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   621
by (subgoal_tac "Key (serverK(Na,Nb,PRF(PMS,NA,NB))) ~: analz(spies evsa)" 1);
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   622
by (asm_simp_tac (!simpset addsimps [Spy_not_see_MS, 
3480
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   623
				     not_parts_not_analz]) 2);
3474
44249bba00ec Baby TLS. Proofs work, but model seems unrealistic
paulson
parents:
diff changeset
   624
by (Fake_parts_insert_tac 1);
44249bba00ec Baby TLS. Proofs work, but model seems unrealistic
paulson
parents:
diff changeset
   625
qed_spec_mp "TrustServerFinished";
44249bba00ec Baby TLS. Proofs work, but model seems unrealistic
paulson
parents:
diff changeset
   626
44249bba00ec Baby TLS. Proofs work, but model seems unrealistic
paulson
parents:
diff changeset
   627
3685
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   628
(*This version refers not to ServerFinished but to any message from B.
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   629
  We don't assume B has received CertVerify, and an intruder could
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   630
  have changed A's identity in all other messages, so we can't be sure
3519
ab0a9fbed4c0 Changing "lost" from a parameter of protocol definitions to a constant.
paulson
parents: 3515
diff changeset
   631
  that B sends his message to A.  If CLIENT KEY EXCHANGE were augmented
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   632
  to bind A's identity with M, then we could replace A' by A below.*)
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   633
goal thy
3686
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   634
 "!!evs. [| ALL A. Says A Spy (Key (serverK(Na,Nb,M))) ~: set evs; \
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   635
\           evs : tls;  A ~: bad;  B ~: bad;                 \
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   636
\           M = PRF(PMS,NA,NB) |]            \
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   637
\        ==> Notes A {|Agent B, Nonce PMS|} : set evs -->              \
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   638
\            Crypt (serverK(Na,Nb,M)) Y : parts (spies evs)  -->  \
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   639
\            (EX A'. Says B A' (Crypt (serverK(Na,Nb,M)) Y) : set evs)";
3686
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   640
by (etac rev_mp 1);
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   641
by (hyp_subst_tac 1);
3686
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   642
by (analz_induct_tac 1);	(*20 seconds*)
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   643
by (REPEAT_FIRST (rtac impI));
3685
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   644
(*ServerResume, by unicity of PMS*)
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   645
by (blast_tac (!claset addSEs [MPair_parts]
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   646
		       addDs  [Spy_not_see_PMS, 
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   647
			       Notes_Crypt_parts_spies,
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   648
			       Notes_master_imp_Crypt_PMS, unique_PMS]) 4);
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   649
(*ServerFinished, by unicity of PMS (10 seconds)*)
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   650
by (blast_tac (!claset addSEs [MPair_parts]
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   651
		       addDs  [Spy_not_see_PMS, 
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   652
			       Notes_Crypt_parts_spies,
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   653
			       Says_imp_spies RS parts.Inj,
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   654
			       unique_PMS]) 3);
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   655
(*ClientCertKeyEx*)
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   656
by (Blast_tac 2);
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   657
(*Fake: the Spy doesn't have the critical session key!*)
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   658
by (subgoal_tac "Key (serverK(Na,Nb,PRF(PMS,NA,NB))) ~: analz(spies evsa)" 1);
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   659
by (asm_simp_tac (!simpset addsimps [Spy_not_see_MS, 
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   660
				     not_parts_not_analz]) 2);
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   661
by (Fake_parts_insert_tac 1);
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   662
qed_spec_mp "TrustServerMsg";
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   663
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   664
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   665
(*** Protocol goal: if B receives any message encrypted with clientK
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   666
     then A has sent it, ASSUMING that A chose PMS.  Authentication is
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   667
     assumed here; B cannot verify it.  But if the message is
3685
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   668
     ClientFinished, then B can then check the quoted values XA, XB, etc.
3506
a36e0a49d2cd New proofs involving CERTIFICATE VERIFY
paulson
parents: 3500
diff changeset
   669
***)
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   670
goal thy
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   671
 "!!evs. [| evs : tls;  A ~: bad;  B ~: bad |]                         \
3686
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   672
\  ==> (ALL A. Says A Spy (Key(clientK(Na,Nb,PRF(PMS,NA,NB)))) ~: set evs) -->\
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   673
\      Notes A {|Agent B, Nonce PMS|} : set evs -->                  \
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   674
\      Crypt (clientK(Na,Nb,PRF(PMS,NA,NB))) Y : parts (spies evs) -->  \
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   675
\      Says A B (Crypt (clientK(Na,Nb,PRF(PMS,NA,NB))) Y) : set evs";
3686
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   676
by (analz_induct_tac 1);	(*23 seconds*)
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   677
by (REPEAT_FIRST (rtac impI));
3686
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   678
(*ClientResume: by unicity of PMS*)
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   679
by (blast_tac (!claset delrules [conjI]
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   680
		       addSEs [MPair_parts]
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   681
                       addSDs [Notes_master_imp_Notes_PMS]
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   682
	 	       addDs  [good_Notes_unique_PMS]) 4);
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   683
(*ClientFinished: by unicity of PMS*)
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   684
by (blast_tac (!claset delrules [conjI]
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   685
		       addSEs [MPair_parts]
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   686
		       addDs  [good_Notes_unique_PMS]) 3);
3677
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   687
(*ClientCertKeyEx*)
f2569416d18b Now with the sessionK constant and new events ClientAccepts and ServerAccepts
paulson
parents: 3676
diff changeset
   688
by (Blast_tac 2);
3480
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   689
(*Fake: the Spy doesn't have the critical session key!*)
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   690
by (subgoal_tac "Key (clientK(Na,Nb,PRF(PMS,NA,NB))) ~: analz(spies evsa)" 1);
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   691
by (asm_simp_tac (!simpset addsimps [Spy_not_see_MS, 
3480
d59bbf053258 More realistic model: the Spy can compute clientK and serverK
paulson
parents: 3474
diff changeset
   692
				     not_parts_not_analz]) 2);
3474
44249bba00ec Baby TLS. Proofs work, but model seems unrealistic
paulson
parents:
diff changeset
   693
by (Fake_parts_insert_tac 1);
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   694
qed_spec_mp "TrustClientMsg";
3506
a36e0a49d2cd New proofs involving CERTIFICATE VERIFY
paulson
parents: 3500
diff changeset
   695
a36e0a49d2cd New proofs involving CERTIFICATE VERIFY
paulson
parents: 3500
diff changeset
   696
3685
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   697
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   698
(*** Protocol goal: if B receives ClientFinished, and if B is able to
5b8c0c8f576e Full version of TLS including session resumption, but no Oops
paulson
parents: 3683
diff changeset
   699
     check a CertVerify from A, then A has used the quoted
3506
a36e0a49d2cd New proofs involving CERTIFICATE VERIFY
paulson
parents: 3500
diff changeset
   700
     values XA, XB, etc.  Even this one requires A to be uncompromised.
a36e0a49d2cd New proofs involving CERTIFICATE VERIFY
paulson
parents: 3500
diff changeset
   701
 ***)
a36e0a49d2cd New proofs involving CERTIFICATE VERIFY
paulson
parents: 3500
diff changeset
   702
goal thy
3686
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   703
 "!!evs. [| ALL A. Says A Spy (Key(clientK(Na,Nb,PRF(PMS,NA,NB)))) ~: set evs;\
4b484805b4c4 First working version with Oops event for session keys
paulson
parents: 3685
diff changeset
   704
\           Says A' B (Crypt (clientK(Na,Nb,PRF(PMS,NA,NB))) Y) : set evs; \
3676
cbaec955056b Addition of SessionIDs to the Hello and Finished messages
paulson
parents: 3672
diff changeset
   705
\           Says B  A {|Nonce NB, Number SID, Number XB, certificate B KB|}  \
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   706
\             : set evs;                                                  \
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   707
\           Says A'' B (Crypt (priK A)                                    \
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   708
\                       (Hash{|Nonce NB, certificate B KB, Nonce PMS|}))  \
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   709
\             : set evs;                                                  \
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   710
\        evs : tls;  A ~: bad;  B ~: bad |]                             \
3672
56e4365a0c99 TLS now with a distinction between premaster secret and master secret
paulson
parents: 3519
diff changeset
   711
\     ==> Says A B (Crypt (clientK(Na,Nb,PRF(PMS,NA,NB))) Y) : set evs";
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   712
by (blast_tac (!claset addSIs [TrustClientMsg, UseCertVerify]
3683
aafe719dff14 Global change: lost->bad and sees Spy->spies
paulson
parents: 3677
diff changeset
   713
                       addDs  [Says_imp_spies RS parts.Inj]) 1);
3515
d8a71f6eaf40 Now uses the Notes constructor to distinguish the Client (who has chosen M)
paulson
parents: 3506
diff changeset
   714
qed "AuthClientFinished";