Communication Terminal Time Synchronization Replay Attack Prevention
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Solution Overview
Problem
V2X communication systems are vulnerable to replay attacks due to tampering of GPS-derived time information, especially during vehicle parking when the GPS module can be illegally altered, compromising the reliability of time information used for certificate validation.
Innovation Solution
A communication terminal that periodically acquires external time information, encrypts internal time information, and writes it to non-volatile memory, with a processor verifying the validity of the external time information upon initialization by comparing it with the stored internal time information, and optionally using a monotonic counter and message authentication codes to enhance security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If time information is acquired from external GPS, then time synchronization is improved, but vulnerability to replay attacks increases
Solution Approach 1:
The patent applies preliminary action by encrypting time information before storage and performing verification before using the time data. The system encrypts time information obtained from GPS or internal clock using a secret key, stores the encrypted data in non-volatile memory, and verifies its authenticity through decryption and comparison before using it for certificate validation. This prevents replay attacks by ensuring that any tampered time information will be detected during the verification step.
2Ease of operation
If GPS module is accessible during parking, then ease of operation is improved, but security vulnerability increases
Solution Approach 1:
The patent applies preliminary anti-action by pre-encrypting time information with a secret key before storage and preparing verification mechanisms in advance. The encrypted time information stored in non-volatile memory serves as a trusted reference that cannot be easily altered. When the system operates after parking, it decrypts the stored encrypted time information and verifies it against newly acquired time data, thereby counteracting any tampering that may have occurred during the parked state.
3Reliability
If time information is stored in non-volatile memory, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent applies copying by creating an encrypted copy of the time information and storing it in non-volatile memory. The system maintains both the original time information (from GPS or internal clock) and an encrypted copy for verification purposes. This copying approach allows the system to preserve time information reliably across power cycles while using cryptographic techniques to ensure the integrity of the stored copy, preventing undetected tampering.
Data Source
AI summary
The communication terminal includes a communication interface for acquiring external time information from outside and a non-volatile memory and operates as described below. The communication terminal periodically acquires external time information, encrypts the internal time information calibrated based on the acquired external time information, and thereafter writes the encrypted internal time information into the non-volatile memory. In an initialization sequence after power-on of the communication terminal, the communication terminal reads and decrypts internal time information that is lastly written to the non-volatile memory before the power-on, newly acquires external time information, and verifies validity of the acquired external time information by comparing the acquired external time information with the read internal time information.