Given that g is the primitive root and n is the modulus. Party A(sender) secret key be $K_{a}$ and let party B(receiver) secret key be $K_{b}$.
Party A is aware of g,n and $K_{a}$ whereas Party B is aware of g,n and $K_{b}$ . Message sent by A to B will be $M_{ab}$ = $g^{K_{a}}$modn and message sent by party B to A will be $g^{K_{b}}$modn
$M_{ab}$ = 116 mod 23 = 9
$M_{ba}$ = 115 mod 23 = 5
The DH key for party A will be (Mba)6 mod 23 which is equal to DH key for party B which is, (Mab)5 mod 23.
(Mba)6 mod 23 = (Mab)5 mod 23 = (5)6 mod 23 = (9)5 mod 23 = 8
