The vehicle networking software upgrade function has become a standard feature in an increasing number of mass-produced models. Software security upgrades are a key evaluation factor for the degree of intelligence and connectivity in vehicles. The R156 “Software Upgrades and Software Upgrade Management Systems” released by the United Nations World Forum for Vehicle Regulations in 2020, along with China’s upcoming national standard “General Technical Requirements for Automotive Software Upgrades”, both clearly specify requirements for software upgrade security. The vehicle networking software upgrade process mainly includes upgrade package generation, storage, and installation/download. To reduce risks at each stage and ensure compliance during the vehicle upgrade process and safe operation thereafter, China Automotive Intelligent Connectivity Technology Co., Ltd. (hereinafter referred to as “CAICT”) proposes a vehicle networking software upgrade solution based on cryptographic technology, centered around CA and KMS.
Overall Architecture of the Solution
Figure 1 Vehicle Networking Software Upgrade Solution Based on CA and KMS
This solution mainly involves the software upgrade server, signature verification system, KMS system, CDN, and vehicle-side SDK. The software upgrade server collects upgrade demands and generates upgrade tasks and software upgrade packages. The signature verification system signs the upgrade package to ensure data integrity; the KMS system generates dedicated keys for encrypting the upgrade package based on the upgrade task; the encrypted upgrade package, along with a randomly generated identifier for this upgrade task, is transmitted to the CDN system through a two-way authenticated secure channel to ensure the confidentiality of the cloud-stored upgrade package. After the vehicle-side device receives the upgrade push from the software upgrade server, it downloads secure messages such as the signed CDN address and the encryption key for the upgrade package. After successful signature verification, it downloads the encrypted software upgrade package from the specified CDN system. The vehicle-side SDK verifies the authenticity and integrity of the downloaded software upgrade package using the signature certificate obtained from the software upgrade server. After verification, it decrypts the upgrade package using the encryption key and initiates the upgrade program based on the upgrade strategy.
Principle and Function of CA
Figure 2 CA Digital Certificate
The CA digital certificate is issued by the digital certificate authentication system and contains information such as the issuer, issuer’s signature value, user, and user’s public key. Depending on different application scenarios, it is divided into communication certificates, signature certificates, and encryption certificates. Communication certificates are mainly used for establishing SSL/TLS secure channels and can be categorized into one-way and two-way authentication; signature certificates are primarily used for the sender to sign the message’s original value using the corresponding private key of the certificate, proving the authenticity of the sender’s identity; encryption certificates are mainly used for encrypting messages to ensure that only the certificate holder can decrypt them.
Principle and Function of KMS
Figure 3 KMS System Functional Architecture
The KMS system provides full lifecycle management of keys based on cryptographic devices, including the generation, activation, distribution, updating, deactivation, and destruction of symmetric and asymmetric keys. Compared to the method of generating symmetric keys and encrypting them through software, KMS offers higher key protection performance; the key management functionality is more comprehensive, allowing for long-term preservation and management of keys and their relationship with encrypted files; key transmission is doubly encrypted through a secure link, ensuring transmission security.
Figure 4 OTA Solution Patent Certificate
The vehicle networking software upgrade solution based on CA and KMS has successfully applied for a national invention patent and has been applied in multiple pre-production models, passing a series of stringent functional verifications and performance tests by the OEMs, demonstrating good security assurance effects. This solution effectively guarantees the authenticity, integrity, and confidentiality of the software upgrade package at all stages of generation, transmission, storage, download, and installation through the collaborative use of digital certificates, symmetric/asymmetric encryption, and digital signature technologies. Compared to traditional software upgrade solutions, this solution significantly improves security protection effectiveness and implementation efficiency, holding strong practical guidance and promotional significance.
China Automotive Intelligent Connectivity has been deeply engaged in the application of cryptography in vehicle networking for many years, successfully incubating several vehicle networking security service platforms and obtaining multiple invention patents and software copyrights. In the future, CAICT will continue to focus on cryptographic technology to create more vehicle networking security solutions to support the healthy development of the vehicle networking industry.
If you need more information, please feel free to contact us!
Zhang Xiangyu
Phone: 16619931409
Zhang Wang
Phone: 15922090958
China Automotive Data Co., Ltd.
In response to the dual carbon, digital transformation, and “new four modernizations” industrial development trends and innovation development needs, China Automotive Data Co., Ltd. has developed a framework of “one foundation, two wings” to deeply engage in energy saving and low carbon, green ecology, market research, judicial appraisal, and other work, accurately laying out innovative fields such as intelligent networking, intelligent cockpits, and industrial internet (industrial software), forming a business positioning centered on “national-level automotive industry data center, national-level automotive industry chain decision support agency, national-level pan-automotive industry digital support agency.”
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