| role bob (, : agent, | | : symmetric_key, | | % is hash function | | : hash_func, | | Snd, Rcv: channel(dy)) | | % is the user; is the server | | played_by | | def = | | local State: nat, | | , , , , , , , : text, | | % is a secret number to | | % is a secret number to | | , , , , , : text, | | , : text, | | ADD: hash_func, | | , , , , , , , | | , , , , , , : text | | const alice_bob_tc, bob_alice_ts, | | alice_bob_rc, bob_alice_rs, | | subs1, subs2: protocol_id | | init State:= 0 | | transition | | % Registration phase | | % Receive the registration request message from the user | | (1) State = 0 ∧ Rcv(()}_) =∣> | | % Keep secret to and , to | | State′:= 1 ∧ secret(, subs1, ) | | ∧ secret(, , subs2, ) | | % Send the smart card to the user | | ∧ := (()) | | ∧ := xor((), ) | | ∧ := xor(, ()) | | ∧ := xor(, ()) | | ∧ Snd(_) | | % Login phase | | % Receive the login request message | | (2) State = 1 ∧ Rcv(xor(((())), | | xor(, (()))). | | xor(xor(xor((), | | (())), | | (())), ). | | () =∣> | | % Authentication phase | | State′:= 2 ∧ | | % generate a random nonce | | := new() | | % is the current system timestamp | | ∧ := new() | | ∧ := () | | ∧ := xor(xor(xor(xor(xor((), | | (())), | | (())), ), | | ()), ) | | ∧ := () | | ∧ := xor(xor(, ), ) | | ∧ := new() | | ∧ := xor((), ) | | ∧ := (((. | | ) | | % Send the authentication request message | | ∧ Snd() | | % has freshly generated the random nonce for | | ∧ witness(, , bob_alice_rs, ) | | % has freshly generated the timestamp for | | ∧ witness(, , bob_alice_ts, ) | | % Receive the authentication acknowledgement message | | (3) State = 2 ∧ Rcv((ADD()()(). | | ADD()) =∣> | | % ’s acceptance of the value generated for by | | State′:= 3 ∧ request(, , alice_bob_rc, ) | | % ’s acceptance of the value generated for by | | ∧ request(, , alice_bob_tc, ) | | end role |
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