For providing mobility services for users through the global Internet, Mobile IP (MIP) has been standardized by IETF. Since conventional MIP has been investigated without the support of the security, IETF suggests that the current servers capable of performing the authentication, authorization, and accounting (AAA) be used for secure services. However the quality of service (QoS) may be degraded due to inefficiency on integrating the conventional MIP and AAA. For this, we propose a fast and secure handoff mechanism based on IDentification Key (IDK) along with Authentication Value (AV). Also we evaluate the performance of the proposed scheme in terms of the probability of handoff failure and average latency. The results show that our proposed mechanism yields better performance than session key exchange mechaism [11] and ticket based one [12] while maintaining the similar level of security.