Receiver Time-Base Synchronization Using Freshness Value Offsets
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Solution Overview
Problem
In communication protocols, the lack of reliable synchronization between local time bases of communication partners can lead to divergence of freshness values, necessitating periodic or on-demand resynchronization, which can be complex and require high reliability standards.
Innovation Solution
A method for synchronizing the receiver's time base by receiving freshness values from the transmitter, verifying messages based on these values, determining offsets between the transmitter's and receiver's freshness values, and adjusting the receiver's time base accordingly, thereby eliminating the need for a highly reliable freshness value master node.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If periodic or on-demand resynchronization protocols are implemented to maintain freshness value synchronization, then synchronization reliability is improved, but system complexity and cryptographic security requirements increase
Solution Approach 1:
The system performs self-synchronization by having the receiver independently determine the offset between transmitter and receiver freshness values through verification of received messages, eliminating the need for external synchronization protocols or master nodes
Solution Approach 2:
The receiver uses feedback from successful message verifications to determine the offset between transmitter and receiver freshness values, continuously adjusting its time base based on the discrepancy observed in verified messages
2Reliability
If a freshness value master node and synchronization protocol are implemented, then freshness value synchronization is improved, but the number of additional software and hardware components increases
Solution Approach 1:
The invention extracts and eliminates the need for external synchronization infrastructure (master nodes, synchronization protocols) by implementing a self-sufficient offset determination mechanism at the receiver end
Solution Approach 2:
The receiver independently determines its own offset relative to the transmitter using only the message verification process, without requiring any additional synchronization services or components
3Reliability
If high reliability standards are imposed on freshness value master node and synchronization software, then security against replay attacks is improved, but manufacturing and qualification difficulty increases
Solution Approach 1:
The invention replaces expensive, highly reliable synchronization infrastructure with a simple, easily implementable offset determination algorithm that can be qualified and deployed without stringent reliability requirements
Solution Approach 2:
The system uses the existing message verification process to simultaneously determine the offset, eliminating the need for separate high-reliability synchronization software that would require extensive qualification
Data Source
Figure 1~3
AI summary
Embodiments of the present disclosure relate to a vehicle, an apparatus, a data carrier, a computer program, and a method for a receiver of a message and for synchronizing the receiver's time base for generating freshness values. The method comprises receiving the transmitter's freshness values together with messages from the transmitter and verifying the messages based on the freshness values. Further, the method suggests determining an offset of the freshness values which were used for successful verification, to the receiver's freshness values derived from the local time base of the receiver at the time of reception of the messages if the messages are verified successfully.