  Authentication is the first step toward establishing a service provider and
customer (C-P) association. In a mobile network environment, a lightweight and
secure authentication protocol is one of the most significant factors to
enhance the degree of service persistence. This work presents a secure and
lightweight keying and authentication protocol suite termed TAP (Time-Assisted
Authentication Protocol). TAP improves the security of protocols with the
assistance of time-based encryption keys and scales down the authentication
complexity by issuing a re-authentication ticket. While moving across the
network, a mobile customer node sends a re-authentication ticket to establish
new sessions with service-providing nodes. Consequently, this reduces the
communication and computational complexity of the authentication process. In
the keying protocol suite, a key distributor controls the key generation
arguments and time factors, while other participants independently generate a
keychain based on key generation arguments. We undertake a rigorous security
analysis and prove the security strength of TAP using CSP and rank function
analysis.
