Sentinel Logic Circuitry for Embedded Memory Protection
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Solution Overview
Problem
Conventional methods for protecting software intellectual property (IP) in embedded applications against unauthorized access are inadequate, as they rely on simple authentication processes or physical modifications like circuit trace cutting, which do not provide robust protection against sophisticated access attempts.
Innovation Solution
The implementation of sentinel logic circuitry with a protected memory area and an access control circuit that uses a state machine to identify the origin of code execution and control access, allowing only authorized access through a dedicated memory location, enabling nested protection mechanisms for higher security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional authentication processes or physical modifications are used to protect software IP, then access control is provided, but the protection is inadequate against sophisticated access attempts
Solution Approach 1:
The memory is divided into protected and unprotected areas, with the protected area further segmented into code storage and data storage regions. This segmentation isolates critical software IP from unauthorized access while allowing controlled interaction through specific interfaces, thereby improving protection reliability without requiring complete system redesign
Solution Approach 2:
The patent implements nested protection by placing sentinel logic circuitry within the protected memory area, which in turn protects the software IP stored in that area. This creates a layered protection structure where each layer safeguards the next, providing robust protection against sophisticated access attempts while maintaining manageable complexity through hierarchical organization
2Reliability
If sentinel logic circuitry with state machine is implemented to control access, then access control reliability is improved, but device complexity increases
Solution Approach 1:
The sentinel logic circuitry autonomously monitors access requests to the protected memory area and automatically grants or denies access based on the origin of the request. This self-service mechanism eliminates the need for external authentication controllers, improving reliability through consistent automated enforcement while actually reducing overall device complexity by removing redundant control components
Solution Approach 2:
The sentinel logic circuitry acts as an intermediary between the unprotected and protected memory areas, filtering and controlling all access requests. This mediator approach provides reliable access control by centralizing security checks in a dedicated component, simplifying the overall system architecture compared to distributed security mechanisms
3Reliability
If access is restricted only from within protected area or through dedicated location, then security is enhanced, but ease of operation decreases
Solution Approach 1:
The patent extracts the authentication logic from the access control decision process by implementing sentinel logic that automatically identifies the origin of access requests. This extraction allows secure access through dedicated locations without requiring manual authentication steps, thereby maintaining ease of operation while enhancing security through automated origin verification
Data Source
AI summary
A method of protecting software for embedded applications against unauthorized access is disclosed. Software to be protected is loaded into a protected memory area and access to the protected memory area is controlled by sentinel logic circuitry. The sentinel logic circuitry allows access to the protected memory area only either from within the protected memory area or from outside of the protected memory area but through a dedicated memory location within the protected memory area. The dedicated memory location then points to protected address locations within the protected memory area.