Self-Modifying FPGA Configuration for Anti-Tamper Protection
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Solution Overview
Problem
Existing electronic systems, particularly those using FPGAs, face challenges in preventing tampering and protecting secure configuration data, as copying or replication of configuration data can compromise sensitive information, leading to loss of intellectual property and security breaches.
Innovation Solution
A self-modifying FPGA system that includes a configuration memory with both SAFE and dormant data, where the FPGA can switch between safe and secure operating modes by loading configuration data from either PROM or SRAM, using configuration assist circuitry to control data loading and sanitize memory upon tampering detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If configuration data is stored in PROM for FPGA, then the FPGA can be programmed in the field, but the configuration data can be copied or replicated leading to security breaches
Solution Approach 1:
The configuration data is segmented into multiple separate PROMs, each containing only a portion of the total configuration data. The FPGA requires all segments to be present simultaneously to function properly. This segmentation prevents unauthorized copying because obtaining complete configuration data requires access to multiple distributed PROMs rather than a single copyable source.
Solution Approach 2:
The system implements a hierarchical configuration structure where multiple levels of configuration data are nested. The FPGA first loads initial configuration from one PROM, then uses that configuration to access and load additional configuration segments from other PROMs. This nested approach creates multiple access layers that must all be compromised to fully replicate the system.
2Object-affected harmful factors
If multiple configuration PROMs are used to prevent copying, then security is improved, but the device complexity increases
Solution Approach 1:
Multiple PROMs are designed with identical physical interfaces and data formats, allowing them to be universally interchangeable in the configuration loading process. The FPGA's configuration logic is designed to handle multiple PROMs through a standardized interface, reducing the complexity impact by making the system modular and consistent rather than requiring specialized handling for each PROM.
3Object-affected harmful factors
If configuration data is distributed across multiple PROMs, then copying becomes difficult, but the ease of operation decreases
Solution Approach 1:
The system performs preliminary configuration validation by checking the presence and integrity of all required PROM segments before attempting to load configuration data. This preliminary action prevents operational errors by ensuring all necessary components are available, and the system can gracefully handle missing or invalid PROMs without requiring complex error recovery procedures during normal operation.
Data Source
AI summary
A self-modifying FPGA system includes an FPGA and a configuration memory coupled to the FPGA for providing the FPGA with configuration data including SAFE configuration data and dormant configuration data. The SAFE configuration data is initially loaded to the FPGA and the FPGA is configured to a safe operating mode. Upon a determination to proceed to a next step of self modification, dormant configuration data contained in the configuration memory is loaded into the FPGA and the FPGA is configured to a secure operating mode.