Vehicle Head Unit Security for External Device Data Channels

The patent applies preliminary action by performing integrity verification of the smartphone's operating system and application software before establishing the vehicle-dedicated data channel. The vehicle head unit sends an integrity verification request message containing a hash algorithm identifier and initial value, the smartphone calculates the hash value of its software using the provided algorithm, and compares it with a pre-stored reference hash value. Only after successful verification is the data channel established, preventing compromised software from accessing vehicle control functions.

The patent uses an intermediary approach by introducing a plaintext symmetric key as a mediator between the vehicle head unit and smartphone. After successful integrity verification, both parties generate and exchange this key through public key cryptography. The plaintext symmetric key then serves as the foundation for establishing encrypted communication channels, acting as an intermediate security layer that enables secure data transmission without exposing the underlying software integrity verification mechanisms.

The patent applies the taking out principle by extracting the security verification functionality into a separate, standardized protocol layer. Instead of embedding complex verification logic throughout the entire system, the patent creates a dedicated integrity verification message format and protocol that operates independently. The verification process is isolated to specific message exchanges before channel establishment, reducing the complexity burden on the main system architecture.

The patent implements universality by designing a multi-functional integrity verification mechanism that serves multiple purposes: it verifies operating system integrity, verifies application software integrity, and establishes the basis for secure key exchange. The same hash algorithm framework and verification protocol structure can be applied to different software components and communication scenarios, reducing overall system complexity through reuse of standardized procedures.

The patent applies preliminary anti-action by preemptively counteracting potential MITM attacks through integrity verification before key exchange. By verifying the smartphone's software integrity in advance and establishing binding relationships between the verified software and the exchanged keys, the system prevents attackers from intercepting or substituting keys. The preliminary verification creates a trust foundation that neutralizes the risk of information loss during subsequent key exchange operations.

The patent implements feedback mechanisms where the vehicle head unit and smartphone continuously verify each other's identities and software integrity throughout the key exchange and data transmission process. Hash values are calculated and compared, and any discrepancies trigger alerts or connection termination. This feedback loop ensures that if a MITM attack attempts to occur during or after key exchange, the system detects the anomaly and prevents information loss by stopping communication.