Mutable-Field Masking for Secure PTP Packet Transmission
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Solution Overview
Problem
Existing Precision Time Protocol (PTP) networks are vulnerable to security attacks due to unsecured time synchronization solutions, and the implementation of Media Access Control security (MACsec) causes degradation in packet quality and accuracy, particularly in single step PTP methods, which are necessary for critical applications like banking and trading.
Innovation Solution
Implementing modifications in the transmitter and receiver circuits using Advanced Encryption Standard in Galois/Counter Mode (AES-GCM) to mask mutable fields during MACsec processing, adding a post Additional Authenticated Data (AAD) stage for integrity check value (ICV) updates, ensuring secure PTP packet transmission without accuracy loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If MACsec is implemented to secure PTP packets, then security is improved, but packet quality and accuracy degrade
Solution Approach 1:
The patent extracts and masks the mutable fields (timestamp, correction field, checksum) from the PTP packet during MACsec processing. By separating these fields and setting them to masked values, the system prevents MACsec from modifying accuracy-critical data while still applying security protection to the remaining packet contents.
Solution Approach 2:
The patent applies different handling to different parts of the packet: mutable fields are masked and excluded from integrity calculation, while other packet fields undergo normal MACsec processing. This localized differentiation allows security to be applied where needed without compromising accuracy where it matters.
2Reliability
If MACsec processing is applied to PTP packets, then security is improved, but latency increases
Solution Approach 1:
By extracting and masking the mutable fields before MACsec processing, the system reduces the amount of data that requires security processing. This minimizes the processing burden and time required for MACsec operations, thereby reducing latency while maintaining security.
Solution Approach 2:
Instead of applying full MACsec processing to the entire PTP packet, the system applies partial processing only to the non-mutable fields. This partial action approach reduces processing time and latency while still providing adequate security protection.
3Reliability
If mutable fields are included in integrity calculation, then security coverage is improved, but accuracy is compromised
Solution Approach 1:
The patent extracts the mutable fields (timestamp, correction field, checksum) and sets them to masked values before integrity calculation. This ensures these fields are excluded from the integrity calculation, preventing any potential accuracy degradation while maintaining security coverage for other packet fields.
Solution Approach 2:
Instead of including mutable fields in integrity calculation and then trying to correct accuracy issues, the patent inverts the approach by explicitly excluding them from the start. The integrity calculation is performed on the masked packet where mutable fields are set to neutral values, naturally preventing accuracy compromise while maintaining security.
Data Source
AI summary
A transmitter circuit includes a security circuit that masks mutable fields in a packet during an algorithm that generates an authentication tag for the packet, an extraction circuit that extracts the mutable fields from the packet to generate extracted fields, a calculation circuit that calculates updated values for the mutable fields using the extracted fields, and an inserter circuit that inserts the updated values for the mutable fields into the packet.