Group key management is the process of creating, distributing, rotating, and retiring shared encryption keys for a session with multiple participants. In a group call or chat, everyone must be able to decrypt the same protected traffic, but the key must also change when users join, leave, or are removed. That makes the system more complex than one-to-one encryption.
In cyber security, this matters because it determines who can read live media and how much damage a key leak can cause. Strong group key management helps preserve confidentiality, limits exposure after membership changes, and supports properties like forward secrecy. In real-world defenses, it appears in end-to-end encrypted voice and video platforms, where clients handle key updates while the service transports only ciphertext. Weak implementation can lead to failed sessions, outdated clients, or unauthorized access if key handling is broken.