89 lines
2.0 KiB
Plaintext
89 lines
2.0 KiB
Plaintext
# Needham Schroeder Symmetric Key
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#
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# Modelled after the description in the SPORE library
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# http://www.lsv.ens-cachan.fr/spore/nssk.html
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#
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#
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# Note:
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# This protocol uses a ticket so scyther will only be able to verify
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# the protocol using the ARACHNE engine (-a)
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#
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secret k: Function;
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# Model dec that is invertible by inc
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const dec,inc: Function;
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inversekeys(dec,inc);
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usertype SessionKey;
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const Fresh: Function;
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const Compromised: Function;
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protocol needhamschroederSessionKeyCompromise(C)
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{
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// Read the names of 3 agents and disclose a session between them including
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// corresponding session key to simulate key compromise
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role C {
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const Ni,Nr: Nonce;
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const Kir: SessionKey;
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var I,R,S: Agent;
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read_!C1(C,C, I,R,S);
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send_!C2(C,C, (I,R,Ni),
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{Ni,R,Kir,{Kir,I}k(R,S)}k(I,S),
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{Kir,I}k(R,S),
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{Nr}Kir,
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{{Nr}dec}Kir,
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Kir
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);
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claim_C3(C,Empty, (Compromised,Kir));
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}
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}
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protocol needhamschroedersk(I,R,S)
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{
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role I
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{
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const Ni: Nonce;
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var Nr: Nonce;
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var Kir: SessionKey;
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var T: Ticket;
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send_1(I,S,(I,R,Ni));
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read_2(S,I, {Ni,R,Kir,T}k(I,S));
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send_3(I,R,T);
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read_4(R,I,{Nr}Kir);
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send_5(I,R,{{Nr}dec}Kir);
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claim_I2(I,Secret,Kir);
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claim_I3(I,Nisynch);
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claim_I4(I,Empty,(Fresh,Kir));
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}
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role R
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{
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const Nr: Nonce;
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var Kir: SessionKey;
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read_3(I,R,{Kir,I}k(R,S));
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send_4(R,I,{Nr}Kir);
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read_5(I,R,{{Nr}dec}Kir);
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claim_R1(R,Secret,Kir);
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claim_R3(R,Nisynch);
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claim_R4(R,Empty,(Fresh,Kir));
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}
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role S
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{
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var Ni: Nonce;
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const Kir: SessionKey;
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read_1(I,S,(I,R,Ni));
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send_2(S,I,{Ni,R,Kir,{Kir,I}k(R,S)}k(I,S));
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}
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}
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const Alice,Bob,Simon,Eve: Agent;
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untrusted Eve;
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const ne: Nonce;
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compromised k(Eve,Simon);
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