Cryptographic Key Generation Using PUF and Mixed Input Data
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Solution Overview
Problem
Existing methods for generating cryptographic keys in SoCs are costly due to the need for customizing hardware and using technologies like flash memory or OTP memory, which are expensive and space-consuming, and customization of secret data remains costly.
Innovation Solution
A device that generates cryptographic keys using input data of physical unclonable, hardwired, and software types, allowing customization without hardware customization, by assembling these data types into cryptographic elements to produce keys.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If flash memory or OTP memory is used to store secret data in SoC, then customization of cryptographic keys is enabled, but manufacturing cost increases and device area increases
Solution Approach 1:
The patent uses physical unclonable functions (PUF) to generate cryptographic keys based on inherent physical characteristics of the device. Instead of storing secret data in expensive programmable memory, the system copies/uses the unique physical fingerprint of the device itself as the secret, eliminating the need for flash or OTP memory while maintaining customization capability.
Solution Approach 2:
The patent replaces expensive, space-consuming programmable memory structures with a lightweight software-based PUF implementation that uses minimal hardware resources. The cryptographic customization is achieved through software configuration rather than expensive hardware memory structures.
2Adaptability or versatility
If flash memory or OTP memory is used to store secret data in SoC, then customization of cryptographic keys is enabled, but device area increases
Solution Approach 1:
The patent uses physical unclonable functions (PUF) to generate cryptographic keys based on inherent physical characteristics of the device. Instead of storing secret data in expensive programmable memory, the system copies/uses the unique physical fingerprint of the device itself as the secret, eliminating the need for flash or OTP memory while maintaining customization capability.
Solution Approach 2:
The patent changes the approach from storing secret data in hardware memory to using software-configurable parameters that reference physical characteristics. This parameter change allows cryptographic customization without requiring additional memory area in the SoC.
3Ease of manufacture
If secret data are embedded in the netlist of the design, then device shrinkability is improved, but customization of secret data becomes costly
Solution Approach 1:
The patent segments the secret data into two parts: physical characteristics that are inherent to the device (providing uniqueness) and software-configurable parameters (providing customization). This segmentation allows both mass production efficiency and customer-specific customization without requiring costly netlist modifications.
Solution Approach 2:
The patent introduces dynamic configurability through software parameters that can be changed after manufacturing. Instead of fixed secret data embedded in the netlist, the system uses dynamic software configuration to enable customization while maintaining the benefits of standardized manufacturing and device shrinkability.
Data Source
AI summary
A device for generating at least one cryptographic key by selecting at least three input data selected among, on one hand, a predetermined data and, on the other hand, a function of at least one piece of data having a type belonging to the group including: a physical unclonable type, corresponding to physical unclonable function data, a hardwired type, corresponding to data hardwired within said device, and a software type, corresponding to software data, assembling the at least three input data to produce an assembled input data, and applying the assembled input data into a cryptographic element to produce a cryptographic key.