Multi-Phase Re-Keying for Secure Network Synchronization
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Solution Overview
Problem
Existing secure networks face issues with key synchronization and network outages due to conventional re-keying approaches, where group keys become out of sync and expire if the key server is unreachable, leading to communication failures between entities.
Innovation Solution
A multi-phase re-keying method where policy enforcement points (PEPs) support both old and new decryption keys during an overlap period, ensuring seamless communication and key updates are acknowledged before halting the old decryption key, with criteria based on acknowledgments or time intervals for secure and fail-safe key updates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional re-keying approaches are used where old decryption keys are removed immediately after new keys are distributed, then key update speed is improved, but key synchronization reliability deteriorates causing network outages when key servers are unreachable
Solution Approach 1:
The system performs preliminary distribution of new decryption keys to PEPs before removing old decryption keys. This ensures that PEPs have the new keys ready before the transition, preventing synchronization issues. The key server sends new decryption keys to all PEPs in advance, and only after confirmation of successful receipt does it proceed to remove old keys, thereby maintaining reliability while enabling timely updates.
Solution Approach 2:
The system maintains an overlap period where both old and new decryption keys are valid simultaneously. This cushioning period allows PEPs that may have missed the key update to still function using old keys while having new keys available, preventing network outages. The system monitors key usage and ensures smooth transition without forcing immediate key rotation, thus cushioning against synchronization failures.
2Reliability
If the system waits for acknowledgment from all PEPs before removing old decryption keys, then key synchronization reliability is improved, but key update time increases
Solution Approach 1:
The system does not require 100% acknowledgment from all PEPs before proceeding with key rotation. Instead, it uses a threshold-based approach where key removal is triggered when a sufficient majority of PEPs have acknowledged receipt of new keys. This partial action principle allows the system to balance reliability with timely key updates, avoiding excessive waiting while maintaining adequate synchronization.
Solution Approach 2:
The system implements a feedback mechanism where PEPs send acknowledgments to the key server upon successful receipt of new decryption keys. The key server monitors these feedback signals and uses them to determine when to remove old keys. This feedback-driven approach enables dynamic key rotation timing that adapts to the actual state of the network, optimizing the balance between reliability and update speed.
3Reliability
If new decryption keys are distributed to all PEPs before removing old ones, then key synchronization is improved, but security risk increases during the overlap period
Solution Approach 1:
The system dynamically adjusts the validity period of old and new decryption keys based on real-time network conditions and key usage patterns. Rather than using fixed time windows, the system monitors key request patterns and automatically shortens or extends the overlap period as needed. This dynamic approach minimizes the security exposure window while ensuring smooth transitions, adapting to changing security requirements and network states.
Solution Approach 2:
The system changes key parameters such as validity time windows and rotation frequency based on security policies and network conditions. By adjusting these parameters dynamically, the system can reduce the overlap period between old and new keys to minimize security risks, while still maintaining adequate time for key distribution and acknowledgment. Parameter changes allow flexible optimization of the security-reliability trade-off.
Data Source
AI summary
In many secure communication systems, group keys are updated on a regular basis in order to maintain high security level. Decryption and encryption keys are typically updated simultaneously in policy enforcement points (PEPs). Such approach makes the respective communication system prone to dropping of network traffic. According to at least one embodiment, re-keying is performed by installing, at a first phase, a new decryption key at the PEPs without removing an old decryption key previously installed in the PEPs. At a second phase, a new encryption corresponding to the new decryption key is installed and an old encryption key corresponding to the old decryption is removed. At a third stage, the old decryption key and any other old decryption keys are removed from the PEPs.