method and apparatus for obtaining a key, terminal device, computer-readable storage media, method for securely processing the mobility of a terminal device and communications system

摘要

embodiments of this application provide a plurality of methods and devices for obtaining a key, and a plurality of communications systems. a target amf entity determines, using an intermediate key sent by a source amf entity, a communication key used between the target amf entity and a terminal device, or a target amf entity requests a new key from an authentication function entity to determine a communication key used between the target amf entity and a terminal device, and instructs the terminal device to derive a corresponding key. in this way, key isolation is achieved between the target amf entity and the source amf entity, thus effectively avoiding a state of the art security risk and improving network security.