Secure Microcontroller Architecture for Encrypted Model Inference
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Solution Overview
Problem
Data stored in micro-controllers is vulnerable to interception and theft by illegal users, compromising information security.
Innovation Solution
A micro-controller architecture with a secure world and non-secure world, incorporating a key management device, decryption circuit, and memories, enables secure storage and processing of encrypted models, using a processing circuit to generate inference results while protecting the secret key within the secure world.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If data is stored in memory in a micro-controller, then data storage capability is improved, but security against interception and theft by illegal users deteriorates
Solution Approach 1:
The microcontroller is divided into a secure world and a non-secure world, with the secure world isolated to protect sensitive operations like key management and decryption, while the non-secure world handles general data storage and processing. This segmentation prevents illegal users from accessing critical security functions even if they compromise the non-secure world.
Solution Approach 2:
A decryption circuit acts as an intermediary between the encrypted model stored in memory and the processing circuit. The decryption circuit resides in the secure world and uses secret keys to decrypt data before it reaches the processing circuit, preventing direct access to sensitive information even if memory is compromised.
2Adaptability or versatility
If a secret key is stored in the micro-controller for decryption operations, then decryption capability is improved, but security against key extraction by illegal users deteriorates
Solution Approach 1:
The key management device is placed exclusively in the secure world, separated from the non-secure world where illegal users might operate. This ensures that secret keys are stored and managed in an isolated environment that cannot be accessed or compromised by external attacks on the non-secure world.
Solution Approach 2:
The secret key is extracted from general memory storage and placed in a dedicated key management device within the secure world. This extraction removes the key from the vulnerable memory environment and places it in a protected security domain with controlled access.
3Object-affected harmful factors
If an encrypted model is stored in memory, then model security is improved, but processing speed and accessibility deteriorate
Solution Approach 1:
The encrypted model is pre-stored in memory in the non-secure world, and the decryption circuit is pre-configured in the secure world with the necessary secret keys. When processing is needed, the decryption happens quickly through the dedicated decryption circuit without requiring complex security checks during processing, thus maintaining speed while ensuring security.
Data Source
AI summary
A micro-controller including a secure world, a non-secure world, and a processing circuit is provided. The secure world includes a key management device, a decryption circuit, and a first memory. The key management device stores a secret key. The decryption circuit utilizes the secret key to decrypt an encrypted model to generate a decrypted model. The first memory stores the decrypted model. The non-secure world includes a second memory and a third memory. The second memory stores the encrypted model. The third memory stores an inference result. The processing circuit provides input data to the decrypted model. The decrypted model generates the inference result according to the input data.