In order to promote the development of the IoT, the Internet Engineering Task Force (IETF) has been developing a standard named Internet Protocol version 6 (IPv6) over Low Power Wireless Personal Area Networks (6LoWPAN) to enable IP-based sensing devices to connect to the Internet. Besides, to support mobility management, a network-based localized mobility management (NETLMM) protocol named Proxy Mobile IPv6 (PMIPv6) is proposed. Although the 6LoWPAN standard has specified the important issues, security and mobility issues have not been addressed. In this talk, a secure PMIPv6-based mobility scheme is presented. The security scheme enables a 6LoWPAN device to efficiently and securely roam in the 6LoWPAN networks. The formal verification by the Automated Validation of Internet Security Protocols and Applications (AVISPA) and the simulation by JAVA show that the proposed scheme in 6LoWPANs could efficiently enhance the functionalities to prevent various malicious attacks with less computational cost.