Deriving Device-Specific Cryptographic Keys from System-Wide Keys
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Solution Overview
Problem
Existing methods for securely providing device-specific cryptographic keys in computer systems, such as embedded systems, often rely on identical keys across devices, which can be insecure and complex to implement, especially when hardware anchoring is not feasible or is expensive.
Innovation Solution
A method that forms and seals device-specific system identification information during the boot phase, using a combination of parameters unique to each device, to derive a device-specific cryptographic key from a system-wide key, ensuring the key is individualized and secure by being set only once and not changeable during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If identical keys are used across multiple devices to simplify production, then manufacturing complexity is reduced, but security is compromised because keys can be reused and manipulated
Solution Approach 1:
The patent applies local quality by making each device's cryptographic key unique through device-specific system identification information (such as serial numbers, MAC addresses, or hardware fingerprints) while keeping the overall key structure and derivation process standardized. This allows mass production with consistent processes while ensuring each device has locally unique security credentials that cannot be reused on other devices.
2Reliability
If hardware anchoring is used to secure master keys, then key security is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses device-specific system identification information as an intermediary between the master key and the derived cryptographic keys. Instead of directly anchoring master keys in hardware, the system uses software-based identification data (which can be obtained from hardware components without requiring dedicated security hardware) to derive unique keys for each device, thus achieving security without the complexity of hardware anchoring.
Solution Approach 2:
The patent replaces the mechanical/hardware-based key anchoring system with a software-based key derivation system. Instead of using physical security modules or hardware anchors to store and protect master keys, the system uses software algorithms that derive cryptographic keys from device-specific identification information, eliminating the need for complex hardware security infrastructure.
3Reliability
If device-specific identification information is stored in volatile memory during boot phase, then key derivation security is improved, but the system becomes vulnerable to manipulation during operation
Solution Approach 1:
The patent applies preliminary action by performing the sealing of device-specific system identification information during the boot phase, before the device enters normal operation. The identification data is written to non-volatile memory during initialization and then sealed, making it immutable during subsequent operation. This ensures that the data used for key derivation is established under controlled conditions and cannot be manipulated later, while the derived keys remain secure throughout device operation.
Data Source
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AI summary
The invention relates to a method and an apparatus for securely providing a device-specific cryptographic key from a system-wide key for a device and a computer program product comprising a computer program, which comprises means for carrying out said method. At least one item of device-specific system identification information is formed and sealed for this purpose while a boot code is executed and the device-specific cryptographic key is formed from a system-wide key by using the at least one item of device-specific system identification information.