scyther/spdl/boyd.spdl
2005-03-14 13:42:15 +00:00

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usertype Sessionkey;
usertype Macseed;
secret k: Function;
const m: Function;
secret unm: Function;
const f: Function;
inversekeys (m, unm);
/*
* Boyd key agreement
*
* Boyd & Mathuria: Protocols for authentication and key establishment
* (2003) p. 101
*
* Note that MAC_ks(x) has been interpreted as MAC(x,ks); this
* assumption causes some possible false attacks.
*/
protocol boyd(I,R,S)
{
role I
{
const ni: Nonce;
var nr: Nonce;
var ks: Macseed;
send_1 (I,S, I,R, ni );
read_3 (R,I, { I,R, ks }k(I,S), m(ni, m(ks,ni,nr)), nr );
send_4 (I,R, m(nr, m(ks,ni,nr)) );
claim_6 (I, Secret, m(ks,ni,nr) );
claim_7 (I, Niagree);
claim_8 (I, Nisynch);
}
role R
{
var ni: Nonce;
const nr: Nonce;
var ks: Macseed;
read_2 (S,R, { I,R, ks }k(I,S), { I,R, ks }k(R,S), ni );
send_3 (R,I, { I,R, ks }k(I,S), m(ni, m(ks,ni,nr)), nr );
read_4 (I,R, m(nr, m(ks,ni,nr)) );
claim_10 (R, Secret, m(ks,ni,nr));
claim_11 (R, Niagree);
claim_12 (R, Nisynch);
}
role S
{
var ni,nr: Nonce;
const ks: Macseed;
read_1 (I,S, I,R, ni );
send_2 (S,R, { I,R, ks }k(I,S), { I,R, ks }k(R,S), ni );
}
}
const Alice,Bob,Simon,Eve: Agent;
untrusted Eve;
const ne: Nonce;
const mcsde: Macseed;
const ke: Sessionkey;
compromised k(Eve,Eve);
compromised k(Eve,Alice);
compromised k(Eve,Bob);
compromised k(Eve,Simon);
compromised k(Alice,Eve);
compromised k(Bob,Eve);
compromised k(Simon,Eve);
run boyd.I(Agent,Agent,Simon);
run boyd.R(Agent,Agent,Simon);
run boyd.S(Agent,Agent,Simon);
run boyd.I(Agent,Agent,Simon);
run boyd.R(Agent,Agent,Simon);
run boyd.S(Agent,Agent,Simon);