Multi-Link Security Key Management for Replay Attack Mitigation

The patent segments the key management approach by allowing different PMKs to be used for different links (e.g., 2.4 GHz link and 5 GHz link). Each link can have its own PMK, PTK, GTK, and IGTK, which are managed independently. This segmentation enables replay attack detection per link while maintaining organized key storage through separate key hierarchies for each link.

The patent introduces dynamic key selection capability where the system can adaptively choose between using the same PMK across all links or different PMKs per link based on security requirements. The key management is made flexible through dynamic key derivation functions that can generate link-specific keys from a common PMK when needed, or use separate PMKs when enhanced security is required.

The patent implements preliminary key derivation where Pairwise Transient Keys (PTKs) are derived in advance from the Pairwise Master Key (PMK) before actual data transmission begins. The key negotiation process includes pre-establishing the key hierarchy and deriving all necessary keys (PTK, GTK, IGTK) during the initial association phase, so that when data transmission starts, the keys are already ready and no additional negotiation time is needed.

The patent applies local quality by allowing different IGTKs to be used for different links based on their specific security requirements. Each link can have its own IGTK for protecting broadcast and multicast frames, enabling tailored security approaches for each link's characteristics while maintaining overall system security.