SummaryAuthentication is the first step toward establishing a service provider and customer 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 time‐assisted authentication protocol (TAP). The TAP improves the security of protocols with the assistance of time‐based encryption keys and scales down the authentication complexity by issuing a reauthentication ticket. While moving across the network, a mobile customer node sends a reauthentication 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 communicating sequential processes and rank function analysis.