scyther/gui/Protocols/wmf-lowe.spdl
2007-05-19 17:10:46 +02:00

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# Lowe modified Wide Mouthed Frog
#
# Modelled after the description in the SPORE library
# http://www.lsv.ens-cachan.fr/spore/wideMouthedFrogLowe.html
#
# Note:
# According to SPORE there are no known attacks on this protocol, scyther
# finds one however this has to do with the unusual assumption that every
# agent can recognise and will reject to read messages that it has created
# itself.
usertype SessionKey;
usertype TimeStamp;
usertype ExpiredTimeStamp;
const succ,pred: Function;
inversekeys (succ,pred);
const Fresh: Function;
const Compromised: Function;
secret k: Function;
protocol wmf-Lowe^KeyCompromise(C)
{
// Read the names of 3 agents and disclose a session between them including
// corresponding session key to simulate key compromise
role C {
const Ni,Nr: Nonce;
const Kir: SessionKey;
const Ti,Ts: ExpiredTimeStamp;
var I,R,S: Agent;
read_!C1(C,C, I,R,S);
send_!C2(C,C, I, {I,Ti,R,Kir}k(I,S),
{S,Ts,I,Kir}k(R,S),
{R,Nr}Kir,
{I,{Nr}succ}Kir,
Kir
);
claim_C3(C,Empty, (Compromised,Kir));
}
}
protocol wmf-Lowe(I,R,S)
{
role I
{
const Kir: SessionKey;
const Ti: TimeStamp;
var Kr: SessionKey;
var Nr: Nonce;
send_1(I,S, I, {Ti, R, Kir}k(I,S));
read_3(R,I,{Nr}Kir);
send_4(I,R,{{Nr}succ}Kir);
claim_I1(I,Secret,Kir);
claim_I2(I,Nisynch);
claim_I3(I,Empty,(Fresh,Kir));
}
role R
{
var Ts: TimeStamp;
var Kir: SessionKey;
const Nr: Nonce;
read_2(S,R, {Ts, I, Kir}k(R,S) );
send_3(R,I, {Nr}Kir);
read_4(I,R, {{Nr}succ}Kir);
claim_R1(R,Secret,Kir);
claim_R2(R,Nisynch);
claim_R3(R,Empty,(Fresh,Kir));
}
role S
{
var Kir: SessionKey;
const Ts: TimeStamp;
var Ti: TimeStamp;
read_1(I,S, I,{Ti, R, Kir}k(I,S) );
send_2(S,R, {Ts, I, Kir}k(R,S));
}
}
const Alice,Bob,Eve,Simon: Agent;
const Ke: SessionKey;
const Te: TimeStamp;
untrusted Eve;
compromised k(Eve,Simon);