79 lines
1.5 KiB
Plaintext
79 lines
1.5 KiB
Plaintext
/*
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* KSL from SPORE
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*
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* Messages 6-8 are intended for repeated authentication, and there are
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* known attacks on this. However, we don't model that yet.
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*
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* Furthermore, it is interesting to experiment here with key
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* compromise (of kab), when this is implemented in Scyther.
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*/
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usertype Server, SessionKey, GeneralizedTimestamp, Ticket, TicketKey;
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secret k: Function;
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const s: Server;
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/* give the intruder something to work with */
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const kee: SessionKey;
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untrusted e;
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compromised k(e,s);
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protocol ksl(A,B,S)
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{
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role A
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{
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fresh Na, Ma: Nonce;
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var Nc, Mb: Nonce;
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var T: Ticket;
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var Kab: SessionKey;
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send_1(A,B, Na, A);
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recv_4(B,A, { Na,B,Kab }k(A,S), T, Nc, {Na}Kab );
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send_5(A,B, { Nc }Kab );
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send_6(A,B, Ma,T );
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recv_7(B,A, Mb,{Ma}Kab );
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send_8(A,B, {Mb}Kab );
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claim_A1(A,Secret, Kab);
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claim_A2(A,Niagree);
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claim_A3(A,Nisynch);
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}
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role B
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{
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var Na,Ma: Nonce;
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fresh Nb,Nc,Mb: Nonce;
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var Kab: SessionKey;
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fresh Kbb: TicketKey;
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fresh Tb: GeneralizedTimestamp;
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var T: Ticket;
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recv_1(A,B, Na, A);
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send_2(B,S, Na, A, Nb, B );
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recv_3(S,B, { Nb, A, Kab }k(B,S), T );
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send_4(B,A, T, { Tb, A, Kab }Kbb, Nc, {Na}Kab );
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recv_5(A,B, { Nc }Kab );
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recv_6(A,B, Ma,{ Tb, A, Kab }Kbb );
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send_7(B,A, Mb,{Ma}Kab );
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recv_8(A,B, {Mb}Kab );
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claim_B1(B,Secret, Kab);
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claim_B2(B,Niagree);
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claim_B3(B,Nisynch);
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}
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role S
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{
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var Na, Nb: Nonce;
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fresh Kab: SessionKey;
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recv_2(B,S, Na, A, Nb, B );
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send_3(S,B, { Nb, A, Kab }k(B,S), { Na,B,Kab }k(A,S) );
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}
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}
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