usertype SessionKey; secret k: Function; protocol andrewLoweBan(I,R) { role I { fresh ni: Nonce; var nr: Nonce; var kir: SessionKey; send_1(I,R, I,ni ); recv_2(R,I, {ni,kir,I}k(I,R) ); send_3(I,R, {ni}kir ); recv_4(R,I, nr ); claim_5(I,Nisynch); claim_5b(I,Niagree); claim_6(I,Secret, kir); claim_7(I,Secret, k(I,R)); } role R { var ni: Nonce; fresh nr: Nonce; fresh kir: SessionKey; recv_1(I,R, I,ni ); send_2(R,I, {ni,kir,I}k(I,R) ); recv_3(I,R, {ni}kir ); send_4(R,I, nr ); claim_8(R,Nisynch); claim_8b(R,Niagree); claim_9(R,Secret, kir); claim_10(R,Secret, k(I,R)); } } const kee: SessionKey;