Cryptographic Synchronization Counter Extraction
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Solution Overview
Problem
Conventional authentication schemes in wireless communication systems, such as WiMAX, are vulnerable to replay attacks and inefficient due to the need for caching and maintaining records of secret keys and counters, which consume storage and create security vulnerabilities.
Innovation Solution
A method of cryptographic synchronization that involves transmitting and receiving messages with incremented counters, allowing validation of freshness without caching the entire AK context, using a tuple with uplink and downlink counter values to authenticate mobile units and base stations, reducing storage needs and preventing replay attacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional authentication schemes use message authentication codes with counters and secret keys, then authentication security is provided, but storage requirements increase and replay attacks remain vulnerable
Solution Approach 1:
The patent extracts only the essential counter values from the complete AK context that needs to be stored. Instead of caching all secret key material and counter states, the system extracts and transmits minimal counter information (CMAC_PN_U and CMAC_REG_D values) that is sufficient for authentication verification, thereby reducing storage requirements while maintaining security
Solution Approach 2:
The patent performs preliminary authentication validation by having the mobile unit calculate message authentication codes using its local counters and secret keys before transmission. The base station then validates these pre-calculated codes against freshly generated codes, allowing authentication to occur without the base station needing to store extensive historical counter data
2Reliability
If conventional schemes cache AK context for all base stations and mobile units, then replay attacks are prevented, but device complexity and storage increase
Solution Approach 1:
The patent extracts only the necessary counter values (CMAC_PN_U from mobile unit and CMAC_REG_D from base station) from the complete AK context. These extracted counter values are transmitted in authentication messages, allowing replay attack prevention through counter validation without requiring complex caching of entire AK contexts at each device
Solution Approach 2:
The patent introduces counter values as intermediary elements that mediate between the mobile unit and base station for authentication. Instead of directly comparing complex AK contexts, the system uses these intermediary counter values (embedded in message authentication codes) to verify freshness and prevent replay attacks, simplifying the authentication mechanism
Data Source
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AI summary
The present invention provides a method of cryptographic synchronization. The method may include providing information indicative of a first counter to a first one of a plurality of base stations. The first counter is incremented prior to each message transmitted to each of the plurality of base stations. The method may also include authenticating at least one first message received from the first one of the plurality of base stations in response to providing the information indicative of first counter.