Network Time Synchronization with Nonce-Based Authentication
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Solution Overview
Problem
Traditional time synchronization schemes lack security measures, making them vulnerable to interference from malicious entities that can spoof or replay time messages, potentially disrupting scheduled operations.
Innovation Solution
The implementation of a protocol that includes integrity check values (ICVs) and nonces in time synchronization messages, processed by secure circuits, to authenticate and prevent tampering, and determine valid timestamps by calculating propagation delays and offsets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional time synchronization protocols are used, then time coordination is achieved, but security against spoofing and replay attacks is insufficient
Solution Approach 1:
The patent applies preliminary action by pre-generating and storing multiple future timestamps in advance at the time source. These pre-generated timestamps are stored in a buffer and made available for retrieval by clients without requiring real-time generation. This approach enhances security by ensuring timestamps cannot be spoofed or replayed, as each timestamp is unique and pre-validated, while avoiding the complexity of real-time cryptographic timestamp generation at the client side.
Solution Approach 2:
The patent introduces an intermediary approach by using a centralized time source that acts as a trusted mediator between clients and the time synchronization process. The time source generates and distributes authoritative timestamps to multiple clients, and clients validate these timestamps against their local clocks. This intermediary model centralizes the security function, preventing clients from generating their own timestamps that could be spoofed, while maintaining relatively simple client-side implementation through validation logic.
2Measurement precision
If propagation delay calculation is implemented, then synchronization accuracy is improved, but message exchange complexity increases
Solution Approach 1:
The patent extracts the propagation delay calculation from the core timestamp validation process. Instead of requiring complex bidirectional message exchanges to measure round-trip time, the system separates the timestamp distribution function from the delay measurement function. Clients can optionally perform delay calculations using simplified unidirectional message exchanges where the client sends a request and the time source responds with both the timestamp and the measured propagation delay, thereby improving accuracy without significantly increasing overall system complexity.
Data Source
AI summary
Techniques are disclosed relating to time synchronization in a network. In some embodiments, an apparatus includes a first circuit having a first clock configured to maintain a local time value for a node coupled to a network. The first circuit is configured to send a first message to a second circuit. The first message includes a first nonce. The second circuit has a second clock that maintains a reference time value for the network. The first circuit receives a second message from the second circuit, the second message including a second nonce and is associated with a timestamp identifying the reference time value. The first circuit compares the first nonce to the second nonce to determine whether the timestamp is valid and, in response to determining that the timestamp is valid, uses the timestamp to synchronize the first clock with the second clock.