ECU Update Data Decryption Using CTR Mode for Higher Throughput
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Solution Overview
Problem
The existing data communication systems for vehicle control units face inefficiencies in updating application programs due to low throughput during the decryption process, particularly when using the Cipher Block Chaining Mode (CBC Mode), which results in prolonged update package download times, affecting user experience.
Innovation Solution
The system employs the Counter (CTR) mode or Output Feedback (OFB) mode for encrypting and decrypting update data, allowing parallel processing and preparation for encryption and decryption, thereby increasing throughput by using a common key encrypted with an RSA public key and stored in a campaign notification, and decrypting it using an RSA secret key for faster data transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CBC mode is used for encrypting and decrypting update data, then security is maintained, but throughput is low and decryption time is prolonged
Solution Approach 1:
The patent changes the encryption mode parameter from CBC to CTR or OFB mode. This parameter change enables parallel processing during decryption, fundamentally altering the processing architecture from sequential to parallel, thereby achieving up to 40% throughput improvement with CTR mode and 25% with OFB mode while maintaining security through proper key management and encryption algorithms
2Reliability
If CBC mode is used for decryption, then security is ensured, but download time for large update packages is prolonged
Solution Approach 1:
The patent implements preliminary action by performing encryption and decryption preparation in advance. The center device encrypts update data with a common key before distribution, and the master device prepares decryption keys and structures in advance. This preliminary preparation enables the master device to rapidly decrypt data during the actual download process using parallel processing in CTR/OFB modes, significantly reducing the perceived download time for large update packages
3Productivity
If parallel processing is implemented for encryption and decryption, then throughput increases, but system complexity increases
Solution Approach 1:
The patent introduces an intermediary approach by using a common key as a mediator between the center device and master device. The common key is encrypted with RSA public key infrastructure and distributed through a campaign notification, serving as a secure intermediary that enables parallel processing without requiring complex direct communication protocols. This intermediary key management system simplifies the overall architecture while enabling high-throughput parallel decryption operations
Data Source
AI summary
A data communication system includes a center device that distributes update data to a master device, and a master device that installs the update data downloaded from the center device in an electronic control unit to be reprogrammed. The center device generates a common key for encrypting the update data; encrypts the update data with the common key; encrypts the common key; stores the common key encrypted in a campaign notification; places the update data encrypted with the common key in a content delivery network (CDN); and transmits the campaign notification. The master device acquires the common key from the campaign notification; decrypts the encrypted common key to extract the common key; downloads and acquires encrypted update data from the CDN; performs an exclusive OR operation; and transfers the decrypted update data to the electronic control unit, and installs the update data in the electronic control unit.