Patent attributes
A method for security handling in a mobility of a terminal device, where the method includes: a target access and mobility management function (AMF) entity receiving a first message for registering a terminal device; the target AMF entity sending a second message to a source AMF entity after receiving the first message; the source AMF entity deriving a first key based on a key between the source AMF entity and the terminal device; the source AMF entity sending the first key to the target AMF entity; the target AMF entity determining to use the first key based on security related information after receiving the first key; and the target AMF entity determining a communication key between the target AMF entity and the terminal device based on the first key after determining to use the first key.