The Diffie-Hellman Authentication Test in the Strand-Space Mode

To reduce the computational complexity of the protocol, a transformed method of Diffie-Hellman key exchange scheme is used as an authentication test in some protocols. The paper proposes a way in which protocols that use the transformed method can be verified by using strand space model. First, the adversary´s behavior is extended, and the three concepts of transformed edge, transforming edge and test component for strand space are redefined. Then, strand space terminology is used to define an authentication test that is guaranteed by the Diffie-Hellman problem. The applicability and usefulness of this authentication test are demonstrated by analyzing a sample protocol. Furthermore, the unknown key share attack, which takes this protocol as an aim, is given in this paper, and it has not been found by the others. Eventually, an improved method is proposed which can remedy the fault.