In-Vehicle OTA Session Keys for Secure Sub-Processor Upgrades
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Solution Overview
Problem
Current in-vehicle network communication lacks identity authentication and encryption, making it vulnerable to illegal OTA activities and compromising vehicle security.
Innovation Solution
Implementing a method that generates temporary communication keys using random numbers and a root key for encrypted communication between a main processor and sub-processors, with integrity checks using MAC values to ensure secure data exchange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If identity authentication and encryption are implemented in in-vehicle network OTA communication, then communication security is improved, but system complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring root keys in the main processor and sub-processor before communication begins. The authentication framework, including key generation algorithms and MAC verification mechanisms, is established in advance. This allows the system to quickly perform secure authentication and encryption during OTA operations without adding complex real-time processing requirements, thus improving communication security while controlling system complexity.
Solution Approach 2:
The patent utilizes parameter changes by dynamically generating temporary communication keys through random number generation during each OTA session. The encryption parameters (keys) change for each communication session rather than using static keys, providing forward security. This approach enhances communication security through cryptographic transformations while maintaining manageable system complexity by using standardized cryptographic algorithms.
2Reliability
If temporary communication keys are generated using random numbers and root keys, then key security is improved, but computation time increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring root keys in both the main processor and sub-processor during manufacturing. These root keys serve as the foundation for all subsequent temporary key generation. By having the cryptographic foundation ready in advance, the system can quickly generate session-specific temporary keys during OTA operations without requiring time-consuming key establishment protocols, thus balancing key security with computation time efficiency.
Solution Approach 2:
The patent uses copying by generating temporary communication keys that are derived from but distinct copies of the root keys combined with random numbers. Each session receives a copied/derived key material that provides the security of the root key without requiring the root key itself to be transmitted or stored in plaintext during communication. This approach enhances key security while maintaining efficient computation through standardized key derivation functions.
3Reliability
If MAC verification is performed for each communication session, then data integrity is improved, but communication overhead increases
Solution Approach 1:
The patent applies parameter changes by using the temporary communication keys (which change each session) to generate unique MAC values for each communication session. The MAC parameter changes with each session based on the session-specific temporary key and random numbers, providing strong data integrity verification. This approach ensures data integrity through cryptographic MAC verification while managing communication overhead by using efficient MAC algorithms and reusing the same key material for multiple messages within a session.
Data Source
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AI summary
An in-vehicle network OTA security communication method and apparatus, a vehicle-mounted system, and a storage medium. The method comprises: sending a communication request to a sub-processor, and receiving a first random number generated by the sub-processor and a check code generated based on the first random number and a root key (101); after the check code is verified to be correct, generating a second random number, concatenating the second random number and the first random number into a random number set, and sending to the sub-processor the random number set and a check code generated based on the random number set and the root key (102); after receiving the information that the verification by the sub-processor succeeds, deriving a temporary communication key on the basis of the random number set for encrypted communication with the sub-processor, and issuing an upgrade package to the sub-processor (103); and after the upgrade package is sent, ending a session and invalidating the temporary key (104). The key for each encryption is randomly generated during in-vehicle network communication, and the OTA service is different each time, thereby avoiding key leakage and replay attacks, and ensuring the security of in-vehicle network OTA communication.