author | berghofe |
Wed, 07 May 2008 10:59:02 +0200 | |
changeset 26807 | 4cd176ea28dc |
parent 25710 | 4cdf7de81e1b |
child 28486 | 873726bdfd47 |
permissions | -rw-r--r-- |
23449 | 1 |
(* Title: HOL/MetisTest/Message.thy |
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ID: $Id$ |
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Author: Lawrence C Paulson, Cambridge University Computer Laboratory |
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Testing the metis method |
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*) |
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theory Message imports Main begin |
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(*Needed occasionally with spy_analz_tac, e.g. in analz_insert_Key_newK*) |
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lemma strange_Un_eq [simp]: "A \<union> (B \<union> A) = B \<union> A" |
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by blast |
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types |
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key = nat |
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consts |
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all_symmetric :: bool --{*true if all keys are symmetric*} |
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invKey :: "key=>key" --{*inverse of a symmetric key*} |
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specification (invKey) |
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invKey [simp]: "invKey (invKey K) = K" |
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invKey_symmetric: "all_symmetric --> invKey = id" |
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by (rule exI [of _ id], auto) |
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text{*The inverse of a symmetric key is itself; that of a public key |
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is the private key and vice versa*} |
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constdefs |
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symKeys :: "key set" |
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"symKeys == {K. invKey K = K}" |
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datatype --{*We allow any number of friendly agents*} |
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agent = Server | Friend nat | Spy |
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datatype |
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msg = Agent agent --{*Agent names*} |
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| Number nat --{*Ordinary integers, timestamps, ...*} |
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| Nonce nat --{*Unguessable nonces*} |
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| Key key --{*Crypto keys*} |
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| Hash msg --{*Hashing*} |
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| MPair msg msg --{*Compound messages*} |
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| Crypt key msg --{*Encryption, public- or shared-key*} |
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text{*Concrete syntax: messages appear as {|A,B,NA|}, etc...*} |
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syntax |
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"@MTuple" :: "['a, args] => 'a * 'b" ("(2{|_,/ _|})") |
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syntax (xsymbols) |
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"@MTuple" :: "['a, args] => 'a * 'b" ("(2\<lbrace>_,/ _\<rbrace>)") |
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translations |
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"{|x, y, z|}" == "{|x, {|y, z|}|}" |
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"{|x, y|}" == "MPair x y" |
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constdefs |
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HPair :: "[msg,msg] => msg" ("(4Hash[_] /_)" [0, 1000]) |
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--{*Message Y paired with a MAC computed with the help of X*} |
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"Hash[X] Y == {| Hash{|X,Y|}, Y|}" |
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keysFor :: "msg set => key set" |
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--{*Keys useful to decrypt elements of a message set*} |
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"keysFor H == invKey ` {K. \<exists>X. Crypt K X \<in> H}" |
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subsubsection{*Inductive Definition of All Parts" of a Message*} |
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inductive_set |
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parts :: "msg set => msg set" |
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for H :: "msg set" |
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where |
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Inj [intro]: "X \<in> H ==> X \<in> parts H" |
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| Fst: "{|X,Y|} \<in> parts H ==> X \<in> parts H" |
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| Snd: "{|X,Y|} \<in> parts H ==> Y \<in> parts H" |
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| Body: "Crypt K X \<in> parts H ==> X \<in> parts H" |
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ML{*ResAtp.problem_name := "Message__parts_mono"*} |
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lemma parts_mono: "G \<subseteq> H ==> parts(G) \<subseteq> parts(H)" |
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apply auto |
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apply (erule parts.induct) |
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apply (metis Inj set_mp) |
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apply (metis Fst) |
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apply (metis Snd) |
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apply (metis Body) |
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done |
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text{*Equations hold because constructors are injective.*} |
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lemma Friend_image_eq [simp]: "(Friend x \<in> Friend`A) = (x:A)" |
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by auto |
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lemma Key_image_eq [simp]: "(Key x \<in> Key`A) = (x\<in>A)" |
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by auto |
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lemma Nonce_Key_image_eq [simp]: "(Nonce x \<notin> Key`A)" |
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by auto |
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subsubsection{*Inverse of keys *} |
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ML{*ResAtp.problem_name := "Message__invKey_eq"*} |
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lemma invKey_eq [simp]: "(invKey K = invKey K') = (K=K')" |
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by (metis invKey) |
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subsection{*keysFor operator*} |
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lemma keysFor_empty [simp]: "keysFor {} = {}" |
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by (unfold keysFor_def, blast) |
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lemma keysFor_Un [simp]: "keysFor (H \<union> H') = keysFor H \<union> keysFor H'" |
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by (unfold keysFor_def, blast) |
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lemma keysFor_UN [simp]: "keysFor (\<Union>i\<in>A. H i) = (\<Union>i\<in>A. keysFor (H i))" |
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by (unfold keysFor_def, blast) |
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text{*Monotonicity*} |
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lemma keysFor_mono: "G \<subseteq> H ==> keysFor(G) \<subseteq> keysFor(H)" |
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by (unfold keysFor_def, blast) |
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lemma keysFor_insert_Agent [simp]: "keysFor (insert (Agent A) H) = keysFor H" |
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by (unfold keysFor_def, auto) |
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lemma keysFor_insert_Nonce [simp]: "keysFor (insert (Nonce N) H) = keysFor H" |
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by (unfold keysFor_def, auto) |
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lemma keysFor_insert_Number [simp]: "keysFor (insert (Number N) H) = keysFor H" |
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by (unfold keysFor_def, auto) |
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lemma keysFor_insert_Key [simp]: "keysFor (insert (Key K) H) = keysFor H" |
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by (unfold keysFor_def, auto) |
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lemma keysFor_insert_Hash [simp]: "keysFor (insert (Hash X) H) = keysFor H" |
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by (unfold keysFor_def, auto) |
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lemma keysFor_insert_MPair [simp]: "keysFor (insert {|X,Y|} H) = keysFor H" |
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by (unfold keysFor_def, auto) |
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lemma keysFor_insert_Crypt [simp]: |
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"keysFor (insert (Crypt K X) H) = insert (invKey K) (keysFor H)" |
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by (unfold keysFor_def, auto) |
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lemma keysFor_image_Key [simp]: "keysFor (Key`E) = {}" |
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by (unfold keysFor_def, auto) |
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lemma Crypt_imp_invKey_keysFor: "Crypt K X \<in> H ==> invKey K \<in> keysFor H" |
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by (unfold keysFor_def, blast) |
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subsection{*Inductive relation "parts"*} |
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lemma MPair_parts: |
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"[| {|X,Y|} \<in> parts H; |
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[| X \<in> parts H; Y \<in> parts H |] ==> P |] ==> P" |
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by (blast dest: parts.Fst parts.Snd) |
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declare MPair_parts [elim!] parts.Body [dest!] |
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text{*NB These two rules are UNSAFE in the formal sense, as they discard the |
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compound message. They work well on THIS FILE. |
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@{text MPair_parts} is left as SAFE because it speeds up proofs. |
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The Crypt rule is normally kept UNSAFE to avoid breaking up certificates.*} |
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lemma parts_increasing: "H \<subseteq> parts(H)" |
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by blast |
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lemmas parts_insertI = subset_insertI [THEN parts_mono, THEN subsetD, standard] |
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lemma parts_empty [simp]: "parts{} = {}" |
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apply safe |
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apply (erule parts.induct) |
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apply blast+ |
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done |
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lemma parts_emptyE [elim!]: "X\<in> parts{} ==> P" |
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by simp |
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text{*WARNING: loops if H = {Y}, therefore must not be repeated!*} |
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lemma parts_singleton: "X\<in> parts H ==> \<exists>Y\<in>H. X\<in> parts {Y}" |
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apply (erule parts.induct) |
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apply fast+ |
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done |
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subsubsection{*Unions *} |
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lemma parts_Un_subset1: "parts(G) \<union> parts(H) \<subseteq> parts(G \<union> H)" |
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by (intro Un_least parts_mono Un_upper1 Un_upper2) |
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lemma parts_Un_subset2: "parts(G \<union> H) \<subseteq> parts(G) \<union> parts(H)" |
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apply (rule subsetI) |
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apply (erule parts.induct, blast+) |
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done |
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lemma parts_Un [simp]: "parts(G \<union> H) = parts(G) \<union> parts(H)" |
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by (intro equalityI parts_Un_subset1 parts_Un_subset2) |
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lemma parts_insert: "parts (insert X H) = parts {X} \<union> parts H" |
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apply (subst insert_is_Un [of _ H]) |
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apply (simp only: parts_Un) |
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done |
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ML{*ResAtp.problem_name := "Message__parts_insert_two"*} |
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lemma parts_insert2: |
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"parts (insert X (insert Y H)) = parts {X} \<union> parts {Y} \<union> parts H" |
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by (metis Un_commute Un_empty_left Un_empty_right Un_insert_left Un_insert_right parts_Un) |
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lemma parts_UN_subset1: "(\<Union>x\<in>A. parts(H x)) \<subseteq> parts(\<Union>x\<in>A. H x)" |
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by (intro UN_least parts_mono UN_upper) |
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lemma parts_UN_subset2: "parts(\<Union>x\<in>A. H x) \<subseteq> (\<Union>x\<in>A. parts(H x))" |
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apply (rule subsetI) |
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apply (erule parts.induct, blast+) |
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done |
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lemma parts_UN [simp]: "parts(\<Union>x\<in>A. H x) = (\<Union>x\<in>A. parts(H x))" |
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by (intro equalityI parts_UN_subset1 parts_UN_subset2) |
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text{*Added to simplify arguments to parts, analz and synth. |
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NOTE: the UN versions are no longer used!*} |
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text{*This allows @{text blast} to simplify occurrences of |
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@{term "parts(G\<union>H)"} in the assumption.*} |
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lemmas in_parts_UnE = parts_Un [THEN equalityD1, THEN subsetD, THEN UnE] |
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declare in_parts_UnE [elim!] |
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lemma parts_insert_subset: "insert X (parts H) \<subseteq> parts(insert X H)" |
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by (blast intro: parts_mono [THEN [2] rev_subsetD]) |
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subsubsection{*Idempotence and transitivity *} |
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lemma parts_partsD [dest!]: "X\<in> parts (parts H) ==> X\<in> parts H" |
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by (erule parts.induct, blast+) |
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lemma parts_idem [simp]: "parts (parts H) = parts H" |
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by blast |
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ML{*ResAtp.problem_name := "Message__parts_subset_iff"*} |
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lemma parts_subset_iff [simp]: "(parts G \<subseteq> parts H) = (G \<subseteq> parts H)" |
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apply (rule iffI) |
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apply (metis Un_absorb1 Un_subset_iff parts_Un parts_increasing) |
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apply (metis parts_idem parts_mono) |
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done |
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lemma parts_trans: "[| X\<in> parts G; G \<subseteq> parts H |] ==> X\<in> parts H" |
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by (blast dest: parts_mono); |
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ML{*ResAtp.problem_name := "Message__parts_cut"*} |
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lemma parts_cut: "[|Y\<in> parts(insert X G); X\<in> parts H|] ==> Y\<in> parts(G \<union> H)" |
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by (metis Un_subset_iff insert_subset parts_increasing parts_trans) |
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subsubsection{*Rewrite rules for pulling out atomic messages *} |
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lemmas parts_insert_eq_I = equalityI [OF subsetI parts_insert_subset] |
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lemma parts_insert_Agent [simp]: |
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"parts (insert (Agent agt) H) = insert (Agent agt) (parts H)" |
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apply (rule parts_insert_eq_I) |
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apply (erule parts.induct, auto) |
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done |
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lemma parts_insert_Nonce [simp]: |
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"parts (insert (Nonce N) H) = insert (Nonce N) (parts H)" |
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apply (rule parts_insert_eq_I) |
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apply (erule parts.induct, auto) |
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done |
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lemma parts_insert_Number [simp]: |
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"parts (insert (Number N) H) = insert (Number N) (parts H)" |
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apply (rule parts_insert_eq_I) |
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apply (erule parts.induct, auto) |
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done |
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lemma parts_insert_Key [simp]: |
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"parts (insert (Key K) H) = insert (Key K) (parts H)" |
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apply (rule parts_insert_eq_I) |
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apply (erule parts.induct, auto) |
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done |
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lemma parts_insert_Hash [simp]: |
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"parts (insert (Hash X) H) = insert (Hash X) (parts H)" |
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apply (rule parts_insert_eq_I) |
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apply (erule parts.induct, auto) |
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done |
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lemma parts_insert_Crypt [simp]: |
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"parts (insert (Crypt K X) H) = |
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insert (Crypt K X) (parts (insert X H))" |
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apply (rule equalityI) |
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apply (rule subsetI) |
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apply (erule parts.induct, auto) |
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apply (blast intro: parts.Body) |
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done |
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lemma parts_insert_MPair [simp]: |
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"parts (insert {|X,Y|} H) = |
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insert {|X,Y|} (parts (insert X (insert Y H)))" |
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apply (rule equalityI) |
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apply (rule subsetI) |
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apply (erule parts.induct, auto) |
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apply (blast intro: parts.Fst parts.Snd)+ |
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done |
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lemma parts_image_Key [simp]: "parts (Key`N) = Key`N" |
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apply auto |
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apply (erule parts.induct, auto) |
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done |
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ML{*ResAtp.problem_name := "Message__msg_Nonce_supply"*} |
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lemma msg_Nonce_supply: "\<exists>N. \<forall>n. N\<le>n --> Nonce n \<notin> parts {msg}" |
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apply (induct_tac "msg") |
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apply (simp_all add: parts_insert2) |
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apply (metis Suc_n_not_le_n) |
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apply (metis le_trans linorder_linear) |
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done |
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subsection{*Inductive relation "analz"*} |
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text{*Inductive definition of "analz" -- what can be broken down from a set of |
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messages, including keys. A form of downward closure. Pairs can |
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be taken apart; messages decrypted with known keys. *} |
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inductive_set |
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analz :: "msg set => msg set" |
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for H :: "msg set" |
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where |
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Inj [intro,simp] : "X \<in> H ==> X \<in> analz H" |
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| Fst: "{|X,Y|} \<in> analz H ==> X \<in> analz H" |
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| Snd: "{|X,Y|} \<in> analz H ==> Y \<in> analz H" |
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| Decrypt [dest]: |
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"[|Crypt K X \<in> analz H; Key(invKey K): analz H|] ==> X \<in> analz H" |
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text{*Monotonicity; Lemma 1 of Lowe's paper*} |
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lemma analz_mono: "G\<subseteq>H ==> analz(G) \<subseteq> analz(H)" |
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apply auto |
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apply (erule analz.induct) |
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apply (auto dest: analz.Fst analz.Snd) |
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done |
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text{*Making it safe speeds up proofs*} |
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lemma MPair_analz [elim!]: |
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"[| {|X,Y|} \<in> analz H; |
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[| X \<in> analz H; Y \<in> analz H |] ==> P |
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|] ==> P" |
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by (blast dest: analz.Fst analz.Snd) |
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lemma analz_increasing: "H \<subseteq> analz(H)" |
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by blast |
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lemma analz_subset_parts: "analz H \<subseteq> parts H" |
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apply (rule subsetI) |
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apply (erule analz.induct, blast+) |
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done |
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lemmas analz_into_parts = analz_subset_parts [THEN subsetD, standard] |
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lemmas not_parts_not_analz = analz_subset_parts [THEN contra_subsetD, standard] |
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ML{*ResAtp.problem_name := "Message__parts_analz"*} |
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lemma parts_analz [simp]: "parts (analz H) = parts H" |
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apply (rule equalityI) |
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apply (metis analz_subset_parts parts_subset_iff) |
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apply (metis analz_increasing parts_mono) |
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done |
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lemma analz_parts [simp]: "analz (parts H) = parts H" |
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apply auto |
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apply (erule analz.induct, auto) |
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done |
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lemmas analz_insertI = subset_insertI [THEN analz_mono, THEN [2] rev_subsetD, standard] |
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subsubsection{*General equational properties *} |
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lemma analz_empty [simp]: "analz{} = {}" |
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apply safe |
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apply (erule analz.induct, blast+) |
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done |
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text{*Converse fails: we can analz more from the union than from the |
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separate parts, as a key in one might decrypt a message in the other*} |
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lemma analz_Un: "analz(G) \<union> analz(H) \<subseteq> analz(G \<union> H)" |
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by (intro Un_least analz_mono Un_upper1 Un_upper2) |
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lemma analz_insert: "insert X (analz H) \<subseteq> analz(insert X H)" |
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by (blast intro: analz_mono [THEN [2] rev_subsetD]) |
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subsubsection{*Rewrite rules for pulling out atomic messages *} |
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lemmas analz_insert_eq_I = equalityI [OF subsetI analz_insert] |
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lemma analz_insert_Agent [simp]: |
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"analz (insert (Agent agt) H) = insert (Agent agt) (analz H)" |
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apply (rule analz_insert_eq_I) |
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apply (erule analz.induct, auto) |
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done |
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lemma analz_insert_Nonce [simp]: |
|
412 |
"analz (insert (Nonce N) H) = insert (Nonce N) (analz H)" |
|
413 |
apply (rule analz_insert_eq_I) |
|
414 |
apply (erule analz.induct, auto) |
|
415 |
done |
|
416 |
||
417 |
lemma analz_insert_Number [simp]: |
|
418 |
"analz (insert (Number N) H) = insert (Number N) (analz H)" |
|
419 |
apply (rule analz_insert_eq_I) |
|
420 |
apply (erule analz.induct, auto) |
|
421 |
done |
|
422 |
||
423 |
lemma analz_insert_Hash [simp]: |
|
424 |
"analz (insert (Hash X) H) = insert (Hash X) (analz H)" |
|
425 |
apply (rule analz_insert_eq_I) |
|
426 |
apply (erule analz.induct, auto) |
|
427 |
done |
|
428 |
||
429 |
text{*Can only pull out Keys if they are not needed to decrypt the rest*} |
|
430 |
lemma analz_insert_Key [simp]: |
|
431 |
"K \<notin> keysFor (analz H) ==> |
|
432 |
analz (insert (Key K) H) = insert (Key K) (analz H)" |
|
433 |
apply (unfold keysFor_def) |
|
434 |
apply (rule analz_insert_eq_I) |
|
435 |
apply (erule analz.induct, auto) |
|
436 |
done |
|
437 |
||
438 |
lemma analz_insert_MPair [simp]: |
|
439 |
"analz (insert {|X,Y|} H) = |
|
440 |
insert {|X,Y|} (analz (insert X (insert Y H)))" |
|
441 |
apply (rule equalityI) |
|
442 |
apply (rule subsetI) |
|
443 |
apply (erule analz.induct, auto) |
|
444 |
apply (erule analz.induct) |
|
445 |
apply (blast intro: analz.Fst analz.Snd)+ |
|
446 |
done |
|
447 |
||
448 |
text{*Can pull out enCrypted message if the Key is not known*} |
|
449 |
lemma analz_insert_Crypt: |
|
450 |
"Key (invKey K) \<notin> analz H |
|
451 |
==> analz (insert (Crypt K X) H) = insert (Crypt K X) (analz H)" |
|
452 |
apply (rule analz_insert_eq_I) |
|
453 |
apply (erule analz.induct, auto) |
|
454 |
||
455 |
done |
|
456 |
||
457 |
lemma lemma1: "Key (invKey K) \<in> analz H ==> |
|
458 |
analz (insert (Crypt K X) H) \<subseteq> |
|
459 |
insert (Crypt K X) (analz (insert X H))" |
|
460 |
apply (rule subsetI) |
|
23755 | 461 |
apply (erule_tac x = x in analz.induct, auto) |
23449 | 462 |
done |
463 |
||
464 |
lemma lemma2: "Key (invKey K) \<in> analz H ==> |
|
465 |
insert (Crypt K X) (analz (insert X H)) \<subseteq> |
|
466 |
analz (insert (Crypt K X) H)" |
|
467 |
apply auto |
|
23755 | 468 |
apply (erule_tac x = x in analz.induct, auto) |
23449 | 469 |
apply (blast intro: analz_insertI analz.Decrypt) |
470 |
done |
|
471 |
||
472 |
lemma analz_insert_Decrypt: |
|
473 |
"Key (invKey K) \<in> analz H ==> |
|
474 |
analz (insert (Crypt K X) H) = |
|
475 |
insert (Crypt K X) (analz (insert X H))" |
|
476 |
by (intro equalityI lemma1 lemma2) |
|
477 |
||
478 |
text{*Case analysis: either the message is secure, or it is not! Effective, |
|
479 |
but can cause subgoals to blow up! Use with @{text "split_if"}; apparently |
|
480 |
@{text "split_tac"} does not cope with patterns such as @{term"analz (insert |
|
481 |
(Crypt K X) H)"} *} |
|
482 |
lemma analz_Crypt_if [simp]: |
|
483 |
"analz (insert (Crypt K X) H) = |
|
484 |
(if (Key (invKey K) \<in> analz H) |
|
485 |
then insert (Crypt K X) (analz (insert X H)) |
|
486 |
else insert (Crypt K X) (analz H))" |
|
487 |
by (simp add: analz_insert_Crypt analz_insert_Decrypt) |
|
488 |
||
489 |
||
490 |
text{*This rule supposes "for the sake of argument" that we have the key.*} |
|
491 |
lemma analz_insert_Crypt_subset: |
|
492 |
"analz (insert (Crypt K X) H) \<subseteq> |
|
493 |
insert (Crypt K X) (analz (insert X H))" |
|
494 |
apply (rule subsetI) |
|
495 |
apply (erule analz.induct, auto) |
|
496 |
done |
|
497 |
||
498 |
||
499 |
lemma analz_image_Key [simp]: "analz (Key`N) = Key`N" |
|
500 |
apply auto |
|
501 |
apply (erule analz.induct, auto) |
|
502 |
done |
|
503 |
||
504 |
||
505 |
subsubsection{*Idempotence and transitivity *} |
|
506 |
||
507 |
lemma analz_analzD [dest!]: "X\<in> analz (analz H) ==> X\<in> analz H" |
|
508 |
by (erule analz.induct, blast+) |
|
509 |
||
510 |
lemma analz_idem [simp]: "analz (analz H) = analz H" |
|
511 |
by blast |
|
512 |
||
513 |
lemma analz_subset_iff [simp]: "(analz G \<subseteq> analz H) = (G \<subseteq> analz H)" |
|
514 |
apply (rule iffI) |
|
515 |
apply (iprover intro: subset_trans analz_increasing) |
|
516 |
apply (frule analz_mono, simp) |
|
517 |
done |
|
518 |
||
519 |
lemma analz_trans: "[| X\<in> analz G; G \<subseteq> analz H |] ==> X\<in> analz H" |
|
520 |
by (drule analz_mono, blast) |
|
521 |
||
522 |
||
523 |
ML{*ResAtp.problem_name := "Message__analz_cut"*} |
|
524 |
declare analz_trans[intro] |
|
525 |
lemma analz_cut: "[| Y\<in> analz (insert X H); X\<in> analz H |] ==> Y\<in> analz H" |
|
526 |
(*TOO SLOW |
|
527 |
by (metis analz_idem analz_increasing analz_mono insert_absorb insert_mono insert_subset) --{*317s*} |
|
528 |
??*) |
|
529 |
by (erule analz_trans, blast) |
|
530 |
||
531 |
||
532 |
text{*This rewrite rule helps in the simplification of messages that involve |
|
533 |
the forwarding of unknown components (X). Without it, removing occurrences |
|
534 |
of X can be very complicated. *} |
|
535 |
lemma analz_insert_eq: "X\<in> analz H ==> analz (insert X H) = analz H" |
|
536 |
by (blast intro: analz_cut analz_insertI) |
|
537 |
||
538 |
||
539 |
text{*A congruence rule for "analz" *} |
|
540 |
||
541 |
ML{*ResAtp.problem_name := "Message__analz_subset_cong"*} |
|
542 |
lemma analz_subset_cong: |
|
543 |
"[| analz G \<subseteq> analz G'; analz H \<subseteq> analz H' |] |
|
544 |
==> analz (G \<union> H) \<subseteq> analz (G' \<union> H')" |
|
545 |
apply simp |
|
546 |
apply (metis Un_absorb2 Un_commute Un_subset_iff Un_upper1 Un_upper2 analz_mono) |
|
547 |
done |
|
548 |
||
549 |
||
550 |
lemma analz_cong: |
|
551 |
"[| analz G = analz G'; analz H = analz H' |
|
552 |
|] ==> analz (G \<union> H) = analz (G' \<union> H')" |
|
553 |
by (intro equalityI analz_subset_cong, simp_all) |
|
554 |
||
555 |
lemma analz_insert_cong: |
|
556 |
"analz H = analz H' ==> analz(insert X H) = analz(insert X H')" |
|
557 |
by (force simp only: insert_def intro!: analz_cong) |
|
558 |
||
559 |
text{*If there are no pairs or encryptions then analz does nothing*} |
|
560 |
lemma analz_trivial: |
|
561 |
"[| \<forall>X Y. {|X,Y|} \<notin> H; \<forall>X K. Crypt K X \<notin> H |] ==> analz H = H" |
|
562 |
apply safe |
|
563 |
apply (erule analz.induct, blast+) |
|
564 |
done |
|
565 |
||
566 |
text{*These two are obsolete (with a single Spy) but cost little to prove...*} |
|
567 |
lemma analz_UN_analz_lemma: |
|
568 |
"X\<in> analz (\<Union>i\<in>A. analz (H i)) ==> X\<in> analz (\<Union>i\<in>A. H i)" |
|
569 |
apply (erule analz.induct) |
|
570 |
apply (blast intro: analz_mono [THEN [2] rev_subsetD])+ |
|
571 |
done |
|
572 |
||
573 |
lemma analz_UN_analz [simp]: "analz (\<Union>i\<in>A. analz (H i)) = analz (\<Union>i\<in>A. H i)" |
|
574 |
by (blast intro: analz_UN_analz_lemma analz_mono [THEN [2] rev_subsetD]) |
|
575 |
||
576 |
||
577 |
subsection{*Inductive relation "synth"*} |
|
578 |
||
579 |
text{*Inductive definition of "synth" -- what can be built up from a set of |
|
580 |
messages. A form of upward closure. Pairs can be built, messages |
|
581 |
encrypted with known keys. Agent names are public domain. |
|
582 |
Numbers can be guessed, but Nonces cannot be. *} |
|
583 |
||
23755 | 584 |
inductive_set |
585 |
synth :: "msg set => msg set" |
|
586 |
for H :: "msg set" |
|
587 |
where |
|
23449 | 588 |
Inj [intro]: "X \<in> H ==> X \<in> synth H" |
23755 | 589 |
| Agent [intro]: "Agent agt \<in> synth H" |
590 |
| Number [intro]: "Number n \<in> synth H" |
|
591 |
| Hash [intro]: "X \<in> synth H ==> Hash X \<in> synth H" |
|
592 |
| MPair [intro]: "[|X \<in> synth H; Y \<in> synth H|] ==> {|X,Y|} \<in> synth H" |
|
593 |
| Crypt [intro]: "[|X \<in> synth H; Key(K) \<in> H|] ==> Crypt K X \<in> synth H" |
|
23449 | 594 |
|
595 |
text{*Monotonicity*} |
|
596 |
lemma synth_mono: "G\<subseteq>H ==> synth(G) \<subseteq> synth(H)" |
|
597 |
by (auto, erule synth.induct, auto) |
|
598 |
||
599 |
text{*NO @{text Agent_synth}, as any Agent name can be synthesized. |
|
600 |
The same holds for @{term Number}*} |
|
601 |
inductive_cases Nonce_synth [elim!]: "Nonce n \<in> synth H" |
|
602 |
inductive_cases Key_synth [elim!]: "Key K \<in> synth H" |
|
603 |
inductive_cases Hash_synth [elim!]: "Hash X \<in> synth H" |
|
604 |
inductive_cases MPair_synth [elim!]: "{|X,Y|} \<in> synth H" |
|
605 |
inductive_cases Crypt_synth [elim!]: "Crypt K X \<in> synth H" |
|
606 |
||
607 |
||
608 |
lemma synth_increasing: "H \<subseteq> synth(H)" |
|
609 |
by blast |
|
610 |
||
611 |
subsubsection{*Unions *} |
|
612 |
||
613 |
text{*Converse fails: we can synth more from the union than from the |
|
614 |
separate parts, building a compound message using elements of each.*} |
|
615 |
lemma synth_Un: "synth(G) \<union> synth(H) \<subseteq> synth(G \<union> H)" |
|
616 |
by (intro Un_least synth_mono Un_upper1 Un_upper2) |
|
617 |
||
618 |
||
619 |
ML{*ResAtp.problem_name := "Message__synth_insert"*} |
|
620 |
||
621 |
lemma synth_insert: "insert X (synth H) \<subseteq> synth(insert X H)" |
|
622 |
by (metis insert_iff insert_subset subset_insertI synth.Inj synth_mono) |
|
623 |
||
624 |
subsubsection{*Idempotence and transitivity *} |
|
625 |
||
626 |
lemma synth_synthD [dest!]: "X\<in> synth (synth H) ==> X\<in> synth H" |
|
627 |
by (erule synth.induct, blast+) |
|
628 |
||
629 |
lemma synth_idem: "synth (synth H) = synth H" |
|
630 |
by blast |
|
631 |
||
632 |
lemma synth_subset_iff [simp]: "(synth G \<subseteq> synth H) = (G \<subseteq> synth H)" |
|
633 |
apply (rule iffI) |
|
634 |
apply (iprover intro: subset_trans synth_increasing) |
|
635 |
apply (frule synth_mono, simp add: synth_idem) |
|
636 |
done |
|
637 |
||
638 |
lemma synth_trans: "[| X\<in> synth G; G \<subseteq> synth H |] ==> X\<in> synth H" |
|
639 |
by (drule synth_mono, blast) |
|
640 |
||
641 |
ML{*ResAtp.problem_name := "Message__synth_cut"*} |
|
642 |
lemma synth_cut: "[| Y\<in> synth (insert X H); X\<in> synth H |] ==> Y\<in> synth H" |
|
643 |
(*TOO SLOW |
|
644 |
by (metis insert_absorb insert_mono insert_subset synth_idem synth_increasing synth_mono) |
|
645 |
*) |
|
646 |
by (erule synth_trans, blast) |
|
647 |
||
648 |
||
649 |
lemma Agent_synth [simp]: "Agent A \<in> synth H" |
|
650 |
by blast |
|
651 |
||
652 |
lemma Number_synth [simp]: "Number n \<in> synth H" |
|
653 |
by blast |
|
654 |
||
655 |
lemma Nonce_synth_eq [simp]: "(Nonce N \<in> synth H) = (Nonce N \<in> H)" |
|
656 |
by blast |
|
657 |
||
658 |
lemma Key_synth_eq [simp]: "(Key K \<in> synth H) = (Key K \<in> H)" |
|
659 |
by blast |
|
660 |
||
661 |
lemma Crypt_synth_eq [simp]: |
|
662 |
"Key K \<notin> H ==> (Crypt K X \<in> synth H) = (Crypt K X \<in> H)" |
|
663 |
by blast |
|
664 |
||
665 |
||
666 |
lemma keysFor_synth [simp]: |
|
667 |
"keysFor (synth H) = keysFor H \<union> invKey`{K. Key K \<in> H}" |
|
668 |
by (unfold keysFor_def, blast) |
|
669 |
||
670 |
||
671 |
subsubsection{*Combinations of parts, analz and synth *} |
|
672 |
||
673 |
ML{*ResAtp.problem_name := "Message__parts_synth"*} |
|
674 |
lemma parts_synth [simp]: "parts (synth H) = parts H \<union> synth H" |
|
675 |
apply (rule equalityI) |
|
676 |
apply (rule subsetI) |
|
677 |
apply (erule parts.induct) |
|
678 |
apply (metis UnCI) |
|
679 |
apply (metis MPair_synth UnCI UnE insert_absorb insert_subset parts.Fst parts_increasing) |
|
680 |
apply (metis MPair_synth UnCI UnE insert_absorb insert_subset parts.Snd parts_increasing) |
|
681 |
apply (metis Body Crypt_synth UnCI UnE insert_absorb insert_subset parts_increasing) |
|
682 |
apply (metis Un_subset_iff parts_increasing parts_mono synth_increasing) |
|
683 |
done |
|
684 |
||
685 |
||
686 |
||
687 |
||
688 |
ML{*ResAtp.problem_name := "Message__analz_analz_Un"*} |
|
689 |
lemma analz_analz_Un [simp]: "analz (analz G \<union> H) = analz (G \<union> H)" |
|
690 |
apply (rule equalityI); |
|
691 |
apply (metis analz_idem analz_subset_cong order_eq_refl) |
|
692 |
apply (metis analz_increasing analz_subset_cong order_eq_refl) |
|
693 |
done |
|
694 |
||
695 |
ML{*ResAtp.problem_name := "Message__analz_synth_Un"*} |
|
696 |
declare analz_mono [intro] analz.Fst [intro] analz.Snd [intro] Un_least [intro] |
|
697 |
lemma analz_synth_Un [simp]: "analz (synth G \<union> H) = analz (G \<union> H) \<union> synth G" |
|
698 |
apply (rule equalityI) |
|
699 |
apply (rule subsetI) |
|
700 |
apply (erule analz.induct) |
|
701 |
apply (metis UnCI UnE Un_commute analz.Inj) |
|
702 |
apply (metis MPair_synth UnCI UnE Un_commute Un_upper1 analz.Fst analz_increasing analz_mono insert_absorb insert_subset) |
|
703 |
apply (metis MPair_synth UnCI UnE Un_commute Un_upper1 analz.Snd analz_increasing analz_mono insert_absorb insert_subset) |
|
704 |
apply (blast intro: analz.Decrypt) |
|
24759 | 705 |
apply blast |
23449 | 706 |
done |
707 |
||
708 |
||
709 |
ML{*ResAtp.problem_name := "Message__analz_synth"*} |
|
710 |
lemma analz_synth [simp]: "analz (synth H) = analz H \<union> synth H" |
|
711 |
proof (neg_clausify) |
|
712 |
assume 0: "analz (synth H) \<noteq> analz H \<union> synth H" |
|
713 |
have 1: "\<And>X1 X3. sup (analz (sup X3 X1)) (synth X3) = analz (sup (synth X3) X1)" |
|
714 |
by (metis analz_synth_Un sup_set_eq sup_set_eq sup_set_eq) |
|
715 |
have 2: "sup (analz H) (synth H) \<noteq> analz (synth H)" |
|
716 |
by (metis 0 sup_set_eq) |
|
717 |
have 3: "\<And>X1 X3. sup (synth X3) (analz (sup X3 X1)) = analz (sup (synth X3) X1)" |
|
718 |
by (metis 1 Un_commute sup_set_eq sup_set_eq) |
|
719 |
have 4: "\<And>X3. sup (synth X3) (analz X3) = analz (sup (synth X3) {})" |
|
720 |
by (metis 3 Un_empty_right sup_set_eq) |
|
721 |
have 5: "\<And>X3. sup (synth X3) (analz X3) = analz (synth X3)" |
|
722 |
by (metis 4 Un_empty_right sup_set_eq) |
|
723 |
have 6: "\<And>X3. sup (analz X3) (synth X3) = analz (synth X3)" |
|
724 |
by (metis 5 Un_commute sup_set_eq sup_set_eq) |
|
725 |
show "False" |
|
726 |
by (metis 2 6) |
|
727 |
qed |
|
728 |
||
729 |
||
730 |
subsubsection{*For reasoning about the Fake rule in traces *} |
|
731 |
||
732 |
ML{*ResAtp.problem_name := "Message__parts_insert_subset_Un"*} |
|
733 |
lemma parts_insert_subset_Un: "X\<in> G ==> parts(insert X H) \<subseteq> parts G \<union> parts H" |
|
734 |
proof (neg_clausify) |
|
735 |
assume 0: "X \<in> G" |
|
736 |
assume 1: "\<not> parts (insert X H) \<subseteq> parts G \<union> parts H" |
|
737 |
have 2: "\<not> parts (insert X H) \<subseteq> parts (G \<union> H)" |
|
738 |
by (metis 1 parts_Un) |
|
739 |
have 3: "\<not> insert X H \<subseteq> G \<union> H" |
|
740 |
by (metis 2 parts_mono) |
|
741 |
have 4: "X \<notin> G \<union> H \<or> \<not> H \<subseteq> G \<union> H" |
|
742 |
by (metis 3 insert_subset) |
|
743 |
have 5: "X \<notin> G \<union> H" |
|
744 |
by (metis 4 Un_upper2) |
|
745 |
have 6: "X \<notin> G" |
|
746 |
by (metis 5 UnCI) |
|
747 |
show "False" |
|
748 |
by (metis 6 0) |
|
749 |
qed |
|
750 |
||
751 |
ML{*ResAtp.problem_name := "Message__Fake_parts_insert"*} |
|
752 |
lemma Fake_parts_insert: |
|
753 |
"X \<in> synth (analz H) ==> |
|
754 |
parts (insert X H) \<subseteq> synth (analz H) \<union> parts H" |
|
755 |
proof (neg_clausify) |
|
756 |
assume 0: "X \<in> synth (analz H)" |
|
757 |
assume 1: "\<not> parts (insert X H) \<subseteq> synth (analz H) \<union> parts H" |
|
758 |
have 2: "\<And>X3. parts X3 \<union> synth (analz X3) = parts (synth (analz X3))" |
|
759 |
by (metis parts_synth parts_analz) |
|
760 |
have 3: "\<And>X3. analz X3 \<union> synth (analz X3) = analz (synth (analz X3))" |
|
761 |
by (metis analz_synth analz_idem) |
|
762 |
have 4: "\<And>X3. analz X3 \<subseteq> analz (synth X3)" |
|
763 |
by (metis Un_upper1 analz_synth) |
|
764 |
have 5: "\<not> parts (insert X H) \<subseteq> parts H \<union> synth (analz H)" |
|
765 |
by (metis 1 Un_commute) |
|
766 |
have 6: "\<not> parts (insert X H) \<subseteq> parts (synth (analz H))" |
|
767 |
by (metis 5 2) |
|
768 |
have 7: "\<not> insert X H \<subseteq> synth (analz H)" |
|
769 |
by (metis 6 parts_mono) |
|
770 |
have 8: "X \<notin> synth (analz H) \<or> \<not> H \<subseteq> synth (analz H)" |
|
771 |
by (metis 7 insert_subset) |
|
772 |
have 9: "\<not> H \<subseteq> synth (analz H)" |
|
773 |
by (metis 8 0) |
|
774 |
have 10: "\<And>X3. X3 \<subseteq> analz (synth X3)" |
|
775 |
by (metis analz_subset_iff 4) |
|
776 |
have 11: "\<And>X3. X3 \<subseteq> analz (synth (analz X3))" |
|
777 |
by (metis analz_subset_iff 10) |
|
778 |
have 12: "\<And>X3. analz (synth (analz X3)) = synth (analz X3) \<or> |
|
779 |
\<not> analz X3 \<subseteq> synth (analz X3)" |
|
780 |
by (metis Un_absorb1 3) |
|
781 |
have 13: "\<And>X3. analz (synth (analz X3)) = synth (analz X3)" |
|
782 |
by (metis 12 synth_increasing) |
|
783 |
have 14: "\<And>X3. X3 \<subseteq> synth (analz X3)" |
|
784 |
by (metis 11 13) |
|
785 |
show "False" |
|
786 |
by (metis 9 14) |
|
787 |
qed |
|
788 |
||
789 |
lemma Fake_parts_insert_in_Un: |
|
790 |
"[|Z \<in> parts (insert X H); X: synth (analz H)|] |
|
791 |
==> Z \<in> synth (analz H) \<union> parts H"; |
|
792 |
by (blast dest: Fake_parts_insert [THEN subsetD, dest]) |
|
793 |
||
794 |
ML{*ResAtp.problem_name := "Message__Fake_analz_insert"*} |
|
795 |
declare analz_mono [intro] synth_mono [intro] |
|
796 |
lemma Fake_analz_insert: |
|
797 |
"X\<in> synth (analz G) ==> |
|
798 |
analz (insert X H) \<subseteq> synth (analz G) \<union> analz (G \<union> H)" |
|
799 |
by (metis Un_commute Un_insert_left Un_insert_right Un_upper1 analz_analz_Un analz_mono analz_synth_Un equalityE insert_absorb order_le_less xt1(12)) |
|
800 |
||
801 |
ML{*ResAtp.problem_name := "Message__Fake_analz_insert_simpler"*} |
|
802 |
(*simpler problems? BUT METIS CAN'T PROVE |
|
803 |
lemma Fake_analz_insert_simpler: |
|
804 |
"X\<in> synth (analz G) ==> |
|
805 |
analz (insert X H) \<subseteq> synth (analz G) \<union> analz (G \<union> H)" |
|
806 |
apply (rule subsetI) |
|
807 |
apply (subgoal_tac "x \<in> analz (synth (analz G) \<union> H) ") |
|
808 |
apply (metis Un_commute analz_analz_Un analz_synth_Un) |
|
809 |
apply (metis Un_commute Un_upper1 Un_upper2 analz_cut analz_increasing analz_mono insert_absorb insert_mono insert_subset) |
|
810 |
done |
|
811 |
*) |
|
812 |
||
813 |
end |