Micro-controller Chip Address Reorder Circuit for External Memory Security

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Solution Overview

Problem

Micro-controller chips face challenges in securely storing program codes in external memory, as the external memory is vulnerable to data theft by third parties.

Innovation Solution

The micro-controller chip is equipped with a central processing unit (CPU), an address reorder circuit, and an address bus, which calculates a unique identifier and seed code to generate a base parameter, reorders internal addresses to create encryption addresses, and transmits these addresses to external memory via the address bus.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If program codes are stored in external memory, then memory space is expanded, but data security is compromised

Engineering Contradiction:

Improvememory spaceVSAvoiddata theft vulnerability

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an address protection circuit as an intermediary component between the CPU and external memory. This circuit encrypts address data before it reaches the external memory, acting as a mediator that protects the communication channel. The encryption circuit transforms readable addresses into encrypted forms, preventing third parties from directly accessing or stealing data even though the memory is externally accessible.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the traditional mechanical/address-based memory access system with an encryption-based system. Instead of directly transmitting addresses to the external memory, the system uses cryptographic transformation to convert addresses into encrypted forms. This substitution of the address transmission mechanism with an encryption mechanism maintains the expanded memory space benefit while eliminating the security vulnerability of direct external access.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Object-affected harmful factors

If address encryption is implemented, then data security is improved, but device complexity increases

Engineering Contradiction:

Improvedata theft protectionVSAvoidcircuit complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent divides the microcontroller system into distinct functional segments: the CPU, the address protection circuit, and the external memory. By segmenting the address generation and address transmission functions into a separate encryption circuit, the system achieves security without requiring the entire system to be restructured. This segmentation allows the encryption functionality to be added as a modular component, limiting the increase in overall device complexity to just the address protection circuit portion.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS12314190B2Micro-controller chip and access method thereof

Publication Date: 2025.05.27 NUVOTON

AI summary

A micro-controller chip is coupled to an external memory and includes a central processing unit (CPU), an address reorder circuit, and an address bus. The CPU is configured to provide a first internal address. The address reorder circuit calculates a unique identifier and a seed code to generate a base parameter and performs a reorder operation for the first internal address according to the base parameter to generate a first encryption address. The address bus is coupled between the address reorder circuit and the external memory to provide the first encryption address to the external memory. The external memory stores specific data according to the first encryption address.