With Trusted Third Party -Final Version Alice A Bob n Authentication (n,B)kA,m Center A,{n,BKA→ B,kabKa2 mkab (n,A,Kabk(B,kab)Ka 1313 With Trusted Third Party – Final Version Alice A Bob n {n, B}KA, m A, {n, B}KA {n, A, kab}KB, {B, kab}KA Authentication Center {B, kab}KA, {m}kab