Mobile IPv6 is an improvement of the original IPv6 protocol, and provides mobility support for IPv6 nodes. However, the security of mobility management is one of the most important issues for MIPv6. Traditional MIPv6 uses IPSec to protect the mobility management, while the dependence on the mechanism of the pre-shared key or certificate limits its applicability. This paper proposes an improved scheme for the original method based on IBC, to protect the mobility management signaling for MIPv6.