src/HOL/Auth/Yahalom.thy
changeset 3519 ab0a9fbed4c0
parent 3481 256f38c01b98
child 3659 eddedfe2f3f8
equal deleted inserted replaced
3518:6e11c7bfb9c7 3519:ab0a9fbed4c0
    10   Proc. Royal Soc. 426 (1989)
    10   Proc. Royal Soc. 426 (1989)
    11 *)
    11 *)
    12 
    12 
    13 Yahalom = Shared + 
    13 Yahalom = Shared + 
    14 
    14 
    15 consts  yahalom   :: agent set => event list set
    15 consts  yahalom   :: event list set
    16 inductive "yahalom lost"
    16 inductive "yahalom"
    17   intrs 
    17   intrs 
    18          (*Initial trace is empty*)
    18          (*Initial trace is empty*)
    19     Nil  "[]: yahalom lost"
    19     Nil  "[]: yahalom"
    20 
    20 
    21          (*The spy MAY say anything he CAN say.  We do not expect him to
    21          (*The spy MAY say anything he CAN say.  We do not expect him to
    22            invent new nonces here, but he can also use NS1.  Common to
    22            invent new nonces here, but he can also use NS1.  Common to
    23            all similar protocols.*)
    23            all similar protocols.*)
    24     Fake "[| evs: yahalom lost;  B ~= Spy;  
    24     Fake "[| evs: yahalom;  B ~= Spy;  
    25              X: synth (analz (sees lost Spy evs)) |]
    25              X: synth (analz (sees Spy evs)) |]
    26           ==> Says Spy B X  # evs : yahalom lost"
    26           ==> Says Spy B X  # evs : yahalom"
    27 
    27 
    28          (*Alice initiates a protocol run*)
    28          (*Alice initiates a protocol run*)
    29     YM1  "[| evs: yahalom lost;  A ~= B;  Nonce NA ~: used evs |]
    29     YM1  "[| evs: yahalom;  A ~= B;  Nonce NA ~: used evs |]
    30           ==> Says A B {|Agent A, Nonce NA|} # evs : yahalom lost"
    30           ==> Says A B {|Agent A, Nonce NA|} # evs : yahalom"
    31 
    31 
    32          (*Bob's response to Alice's message.  Bob doesn't know who 
    32          (*Bob's response to Alice's message.  Bob doesn't know who 
    33 	   the sender is, hence the A' in the sender field.*)
    33 	   the sender is, hence the A' in the sender field.*)
    34     YM2  "[| evs: yahalom lost;  B ~= Server;  Nonce NB ~: used evs;
    34     YM2  "[| evs: yahalom;  B ~= Server;  Nonce NB ~: used evs;
    35              Says A' B {|Agent A, Nonce NA|} : set evs |]
    35              Says A' B {|Agent A, Nonce NA|} : set evs |]
    36           ==> Says B Server 
    36           ==> Says B Server 
    37                   {|Agent B, Crypt (shrK B) {|Agent A, Nonce NA, Nonce NB|}|}
    37                   {|Agent B, Crypt (shrK B) {|Agent A, Nonce NA, Nonce NB|}|}
    38                 # evs : yahalom lost"
    38                 # evs : yahalom"
    39 
    39 
    40          (*The Server receives Bob's message.  He responds by sending a
    40          (*The Server receives Bob's message.  He responds by sending a
    41             new session key to Alice, with a packet for forwarding to Bob.*)
    41             new session key to Alice, with a packet for forwarding to Bob.*)
    42     YM3  "[| evs: yahalom lost;  A ~= Server;  Key KAB ~: used evs;
    42     YM3  "[| evs: yahalom;  A ~= Server;  Key KAB ~: used evs;
    43              Says B' Server 
    43              Says B' Server 
    44                   {|Agent B, Crypt (shrK B) {|Agent A, Nonce NA, Nonce NB|}|}
    44                   {|Agent B, Crypt (shrK B) {|Agent A, Nonce NA, Nonce NB|}|}
    45                : set evs |]
    45                : set evs |]
    46           ==> Says Server A
    46           ==> Says Server A
    47                    {|Crypt (shrK A) {|Agent B, Key KAB, Nonce NA, Nonce NB|},
    47                    {|Crypt (shrK A) {|Agent B, Key KAB, Nonce NA, Nonce NB|},
    48                      Crypt (shrK B) {|Agent A, Key KAB|}|}
    48                      Crypt (shrK B) {|Agent A, Key KAB|}|}
    49                 # evs : yahalom lost"
    49                 # evs : yahalom"
    50 
    50 
    51          (*Alice receives the Server's (?) message, checks her Nonce, and
    51          (*Alice receives the Server's (?) message, checks her Nonce, and
    52            uses the new session key to send Bob his Nonce.*)
    52            uses the new session key to send Bob his Nonce.*)
    53     YM4  "[| evs: yahalom lost;  A ~= Server;  
    53     YM4  "[| evs: yahalom;  A ~= Server;  
    54              Says S A {|Crypt (shrK A) {|Agent B, Key K, Nonce NA, Nonce NB|},
    54              Says S A {|Crypt (shrK A) {|Agent B, Key K, Nonce NA, Nonce NB|},
    55                         X|}  : set evs;
    55                         X|}  : set evs;
    56              Says A B {|Agent A, Nonce NA|} : set evs |]
    56              Says A B {|Agent A, Nonce NA|} : set evs |]
    57           ==> Says A B {|X, Crypt K (Nonce NB)|} # evs : yahalom lost"
    57           ==> Says A B {|X, Crypt K (Nonce NB)|} # evs : yahalom"
    58 
    58 
    59          (*This message models possible leaks of session keys.  The Nonces
    59          (*This message models possible leaks of session keys.  The Nonces
    60            identify the protocol run.  Quoting Server here ensures they are
    60            identify the protocol run.  Quoting Server here ensures they are
    61            correct.*)
    61            correct.*)
    62     Oops "[| evs: yahalom lost;  A ~= Spy;
    62     Oops "[| evs: yahalom;  A ~= Spy;
    63              Says Server A {|Crypt (shrK A)
    63              Says Server A {|Crypt (shrK A)
    64                                    {|Agent B, Key K, Nonce NA, Nonce NB|},
    64                                    {|Agent B, Key K, Nonce NA, Nonce NB|},
    65                              X|}  : set evs |]
    65                              X|}  : set evs |]
    66           ==> Says A Spy {|Nonce NA, Nonce NB, Key K|} # evs : yahalom lost"
    66           ==> Says A Spy {|Nonce NA, Nonce NB, Key K|} # evs : yahalom"
    67 
    67 
    68 
    68 
    69 constdefs 
    69 constdefs 
    70   KeyWithNonce :: [key, nat, event list] => bool
    70   KeyWithNonce :: [key, nat, event list] => bool
    71   "KeyWithNonce K NB evs ==
    71   "KeyWithNonce K NB evs ==