Vehicle Key Derivation Function Model for Secure Management
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Solution Overview
Problem
Current cryptographic key management systems face challenges in efficiently generating and managing unique keys for vehicles, as they require large key databases, are memory-intensive, and lack flexibility, especially when keys need to be updated or shared across different regions and control devices, leading to increased complexity and effort.
Innovation Solution
A key derivation function model is used to generate cryptographic keys from a master key, where key derivation parameters such as key type identification and learning counter are employed to create vehicle-specific keys, reducing the need for storing multiple keys and allowing for secure, flexible key management across various locations and regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If asymmetric cryptography is used to generate keys as random numbers, then key uniqueness and security are improved, but key database size and memory requirements increase significantly
Solution Approach 1:
The patent extracts the essential key material from a master key using a key derivation function, storing only the compact derivation parameters (salt, iteration count) rather than the full cryptographic keys. This reduces the key database size while maintaining security through the computational hardness of reversing the derivation function.
Solution Approach 2:
The patent changes the storage representation from storing complete cryptographic keys to storing derivation parameters (salt value, iteration count, key type identifier). This parameter transformation maintains the ability to generate secure unique keys while dramatically reducing the quantity of data that must be stored and protected.
2Reliability
If multiple individual keys are stored for each vehicle and control device, then key uniqueness is ensured, but system complexity and maintenance effort increase
Solution Approach 1:
The patent implements a universal key derivation function that can generate multiple different cryptographic keys from a single master key and derivation parameters. This multi-functional approach handles vehicle-specific keys, control device-specific keys, and regional keys through the same mechanism, reducing system complexity while ensuring uniqueness.
Solution Approach 2:
The patent segments the key management system into a master key component (stored securely) and derivation parameters (stored with each vehicle/control device). This segmentation allows the system to generate unique keys on-demand without storing all possible keys, reducing management complexity while maintaining uniqueness.
3Reliability
If keys are updated frequently to enhance security, then key security is improved, but the number of key versions and storage requirements increase
Solution Approach 1:
The patent uses the salt value and iteration count as changeable parameters in the key derivation function. When key updates are needed, these parameters are modified to generate new derived keys without changing the master key itself. This approach enhances security through parameter changes while avoiding the need to store multiple complete key versions.
4Adaptability or versatility
If region-specific keys are implemented to meet different country regulations, then adaptability to regional requirements is improved, but the number of different key sets increases
Solution Approach 1:
The patent implements a universal key derivation function that can generate region-specific keys by incorporating regional identifiers into the derivation parameters. The same master key and derivation mechanism serve multiple regions, vehicle types, and control devices, providing regional adaptability without requiring separate key sets for each region.
Data Source
AI summary
The invention relates to a method for generating cryptographic keys according to a key derivation function model. An embodiment includes the following steps: defining a master key for different models of a product type from a manufacturer; defining a set of key derivation parameters for the key derivation function model; determining the key derivation parameters for the model for which a cryptographic key is to be derived; deriving a single cryptographic key or a set of cryptographic keys from the master key according to the key derivation function model taking into account the key derivation parameters, wherein the step of defining a set of key derivation parameters comprises at least the following parameters: key type identification and key type learning counter.