Wireless Key Management Using Primary and Secondary Keys
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Solution Overview
Problem
Existing key distribution methods in wireless communication systems are vulnerable to compromise, as either the old key or key distribution key being compromised can lead to unauthorized access to new keys, and there is a lack of secure methods for updating key distribution keys.
Innovation Solution
The introduction of 'primary keys' and 'secondary keys' in a key management system, where the secondary key can be used for decryption if the primary key fails, allowing secure communication re-establishment and subsequent remote updating of the primary key, with the secondary key being changeable by a field tool but only the primary key by the master device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If symmetric key algorithms are used for key distribution, then computational efficiency is improved, but key distribution security deteriorates because compromised keys can be retrieved by unauthorized agents
Solution Approach 1:
The key management system segments the key hierarchy into multiple levels: root keys at the head end, intermediate keys at distribution nodes, and session keys at end devices. This segmentation isolates compromises to specific segments rather than affecting the entire key system, allowing localized key rotation without compromising other keys.
Solution Approach 2:
The system performs preliminary key distribution through a key installation process where root keys are securely distributed to intermediate nodes before actual communication begins. This preliminary setup establishes a secure key hierarchy that prevents subsequent key compromises from affecting past communications.
2Ease of operation
If key distribution keys are used to encrypt new keys, then key distribution is simplified, but system security deteriorates because all subsequent key changes are compromised if the distribution key is compromised
Solution Approach 1:
The key distribution system is segmented into multiple independent key levels (root keys, intermediate keys, session keys). Each level has its own key management and rotation mechanism, so compromise of one level does not affect other levels. This allows simplified distribution at each level while maintaining overall system security.
Solution Approach 2:
The system implements dynamic key rotation where keys are periodically changed and re-distributed. The key management server can rotate root keys and intermediate keys independently, allowing the system to adapt to security requirements without being locked into a static key distribution scheme that would be compromised by a single key leak.
3Ease of manufacture
If old keys are used to encrypt new keys, then key updates are simplified, but security deteriorates because any listening agent with the old key can discover the new key
Solution Approach 1:
The key update process is segmented into controlled rotations at specific hierarchy levels. Root keys and intermediate keys are rotated independently through the key management server, which manages the distribution of new keys to affected nodes. This segmentation ensures that key updates are simplified at each level while maintaining confidentiality through proper key isolation.
Solution Approach 2:
The key management server acts as an intermediary that centrally manages key distribution and rotation. It receives requests for key updates, generates appropriate new keys, and securely distributes them to the affected intermediate nodes and end devices. This intermediary approach simplifies the update process while maintaining security by controlling the entire key lifecycle.
Data Source
AI summary
A primary key may be used for a first attempt by a remote node to decrypt incoming messages from a master. In the event the decrypt attempt fails at the remote node, a secondary key may then be used to attempt to decrypt the message. Initially, the primary and secondary keys may be the same. A field tool, such as a hand-held programming unit operated by a technician at a remote node location, may change the secondary key, but may not cause any change to the primary key. The secondary key may remain so changed until a new primary key is verified and/or authenticated and the secondary key is overwritten with the new primary key. The primary key may only be changed/set by the master via an encrypted request. A technician may not use a field tool to change a primary key.