Enhanced MMU Memory Segmentation for Microcontroller Data Security
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Solution Overview
Problem
Microcontrollers face vulnerabilities in data security due to malicious software processes and unauthorized access to external data buses and memory, as existing encryption techniques do not adequately protect data from internal threats and external probing.
Innovation Solution
An enhanced memory management unit (MMU) is implemented, coupled with a cryptographic unit and key manager, to restrict access to memory portions based on software processes and encrypt data transmitted over external data buses, using unique encryption keys for each process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If data is stored in external memory and accessed via external data bus, then memory capacity is increased, but data security is compromised due to unauthorized access and probing
Solution Approach 1:
The patent divides memory into multiple secure segments or partitions, each protected by its own access control list (ACL). This segmentation prevents unauthorized access to entire memory regions while allowing legitimate access to specific segments, thus maintaining both large external memory capacity and data security.
Solution Approach 2:
The patent introduces an intermediary security module between the CPU and external memory that intercepts and filters all memory access requests. This intermediary enforces ACL rules, blocking unauthorized access attempts while allowing legitimate operations, thereby protecting external memory without reducing its capacity.
2Object-affected harmful factors
If address encryption is implemented to protect data in external memory, then security against external probing is improved, but security against internal malicious software remains insufficient
Solution Approach 1:
The patent implements different security mechanisms for different access contexts: address encryption for external access and fine-grained ACLs for internal software access. This local differentiation of security qualities addresses both external probing threats and internal malicious software threats appropriately without compromising either aspect.
Solution Approach 2:
The patent combines multiple security mechanisms (address encryption, ACLs, and access control logic) into a composite security system. This multi-layered approach ensures that both external probing attempts and internal malicious software are blocked by different layers of the same security architecture.
3Adaptability or versatility
If all data is accessible to software processes for functionality, then system versatility is maintained, but data security from malicious processes is compromised
Solution Approach 1:
The patent segments memory into multiple protected regions with distinct ACLs that define which software processes can access which data. This allows the system to maintain versatility by supporting multiple processes while preventing malicious processes from accessing data they shouldn't, as each process is restricted to its authorized memory segments.
Solution Approach 2:
The patent implements a feedback mechanism where the security module continuously monitors software process access requests and enforces ACL rules in real-time. This dynamic control ensures that software functionality is maintained for legitimate processes while automatically blocking unauthorized access attempts from malicious processes.
Data Source
AI summary
Apparatus and methods are presented for protecting data in microcontrollers from both malicious software processes running inside the device as well as from unauthorized attempts to read the data from an external data bus and/or external memory. An illustrative embodiment of the invention accomplishes these security improvements, in part, by utilizing an enhanced memory management unit (MMU). The enhanced MMU is configured to prevent one software process running on the microcontroller from accessing data associated with a different software process running on the same microcontroller. Moreover, data transmitted over an external data bus or stored in an external memory is encrypted, thereby reducing the chances that unauthorized users will gain exploitable information from this data.