usertype SessionKey;
secret k: Function;

protocol unknown2(I,R,S)
{
	role I
	{
		fresh ni: Nonce;
		var nr: Nonce;
		var kir: SessionKey;
		var T;

		send_1(I,R, ni );
		recv_3(S,I, { I,R,kir,ni,nr }k(I,S), T );
		send_4(I,R, T, {nr}kir );

		claim_i1(I,Nisynch);
		claim_i2(I,Niagree);
		claim_i3(I,Secret, kir);
	}	
	
	role R
	{
		fresh nr: Nonce;
		var ni: Nonce;
		var kir: SessionKey;

		recv_1(I,R, ni );
		send_2(R,S, { I,R,ni,nr }k(R,S) );
		recv_4(I,R, { I,R,kir,ni,nr }k(R,S), {nr}kir );

		claim_r1(R,Nisynch);
		claim_r2(R,Niagree);
		claim_r3(R,Secret, kir);
	}

	role S
	{
		fresh kir: SessionKey;
		var ni,nr: Nonce;

		recv_2(R,S, { I,R,ni,nr }k(R,S) );
		send_3(S,I, { I,R,kir,ni,nr }k(I,S), { I,R,kir,ni,nr }k(R,S) );

/*
		claim_s1(S,Nisynch);
		claim_s2(S,Niagree);
		claim_s3(S,Secret, kir);
		*/
	}
}


const kee: SessionKey;