Methods, devices, computer programs and carriers for secure management before handover from 5G to 4G systems

摘要

Key management that enables security activation before handing over user devices from a source 5G wireless communication system, ie, next generation system (NGS), to a target 4G wireless communication system, e.g., Evolved Packet System (EPS) / Long Term Evolution (LTE) Is provided. Key management achieves reverse security, i.e. prevents the target 4G wireless communication system from gaining knowledge of the 5G security information used in the source 5G wireless communication system.