Gatekeeper Session Key Distribution via Pre-distribution and Segmentation

The patent implements preliminary action by pre-distributing session keys to GKs before actual communication occurs. During the RAS message exchange phase, GKs along the routing path already possess the session keys, eliminating the need for real-time key distribution during Q.931 message transmission. This pre-positioning of keys resolves the contradiction by securing communication without adding delay during the actual data transfer phase.

The patent applies dynamics by making the key distribution timing flexible - keys are distributed during the setup phase when GKs are establishing routing paths, and the system dynamically adapts to different communication scenarios. GKs can cache keys for multiple potential communication sessions, allowing the system to respond efficiently to varying security requirements without fixed time penalties.

The patent segments the session key into multiple encrypted portions, with each GK receiving only its specific encrypted segment. GKs cannot reconstruct the full session key independently - they must cooperate with other GKs along the path, each contributing their encrypted portion. This segmentation enables key distribution across multiple GKs while preventing any single GK from exposing the complete key, thus resolving the contradiction between distribution capability and security.

The patent introduces encrypted key segments as intermediaries between the session key and individual GKs. Rather than distributing the complete session key directly to each GK, the system uses encrypted portions that serve as intermediaries - these segments are useless without the corresponding decryption keys held by other GKs. This intermediary mechanism enables versatile key distribution while maintaining security through cryptographic protection at each stage.