An efficient mobility management mechanism is one of the major challenges for ubiquitous computing. Recently, the IETF NETLMM working group proposed Proxy Mobile IPv6 (PMIPv6), a network-based localized mobility management protocol to support mobility management without the participation of mobile nodes (MNs) in any mobility-related signaling. Unfortunately, PMIPv6 still suffers from high packet losses and long authentication latency during handover. To address these issues, we propose a secure authentication mechanism and fast handover scheme called SF-PMIPv6 for PMIPv6 networks. The scheme provides low handover latency, supports local authentication procedures, resolves the packet loss problem, and deals with out-of-sequence packets. Moreover, SF-PMIPv6 is a robust authentication scheme that resists various attacks. Our simulation results demonstrate that it provides a better solution than existing schemes.