50 lines
915 B
Plaintext
50 lines
915 B
Plaintext
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// BAN modified version of the yahalom protocol
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//
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// Modeled as version in Paulson's paper:
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// "Relations Between Secrets: Two Formal Analyses of the Yahalom
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// Protocol"
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//
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// Modified (improved) version from page 16.
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usertype Server;
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usertype SessionKey;
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protocol yahalom-BAN-Paulson-modified(A,B,S)
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{
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role A
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{
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fresh na: Nonce;
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var nb: Nonce;
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var ticket: Ticket;
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var kab: SessionKey;
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send_1(A,B, A,na);
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read_3(S,A, nb, {B,kab,na}k(A,S), ticket );
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send_4(A,B, ticket, {nb}kab );
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claim_5(A, Secret,kab);
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}
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role B
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{
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fresh nb: Nonce;
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var na: Nonce;
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var ticket: Ticket;
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var kab: SessionKey;
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read_1(A,B, A,na);
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send_2(B,S, B, nb, {A,na}k(B,S) );
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read_4(A,B, {A,B,kab,nb}k(B,S) , {nb}kab );
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claim_6(B, Secret,kab);
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}
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role S
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{
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fresh kab: SessionKey;
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var na,nb: Nonce;
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read_2(B,S, B, nb, {A,na}k(B,S) );
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send_3(S,A, nb, {B,kab,na}k(A,S), {A,B,kab,nb}k(B,S) );
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}
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}
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