Secure Boot Updates in Memory Devices via Signature Validation

Solution Overview

Problem

Current memory devices, such as eMMC, lack validation mechanisms for boot code images, making them susceptible to tampering, which compromises the integrity of future updates since the boot code managing updates is compromised.

Innovation Solution

A memory device is configured with a write-protected region storing a golden boot image and a public key, allowing secure updates by validating new boot images using the public key and version numbering constraints, with the ability to roll back updates if validation fails.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If boot code images can be updated via boot prompt without validation, then ease of operation is improved, but security and reliability deteriorate due to tampering vulnerability

Engineering Contradiction:

Improveease of boot code updateVSAvoidintegrity of boot code

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The system performs preliminary validation of the boot code image signature against stored public keys before allowing the update to proceed. This preliminary security check ensures that only authenticated and untampered boot images are installed, resolving the contradiction by maintaining ease of operation while preventing tampering through advance verification.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A signature validation mechanism acts as an intermediary between the boot code update process and the actual installation. This intermediary layer verifies the authenticity of incoming boot images using cryptographic signatures and public keys, allowing updates to remain convenient while ensuring their integrity and preventing tampering.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If validation mechanism is added to boot code updates, then reliability is improved, but device complexity increases

Engineering Contradiction:

Improveintegrity of boot codeVSAvoidcomplexity of update system

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system stores copies of public keys in a non-volatile memory region alongside the boot code images. These key copies enable repeated validation of boot image signatures without requiring complex validation infrastructure, improving reliability through simple cryptographic verification while minimizing added complexity.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The validation functionality is extracted as a separate, dedicated validation mechanism that operates independently from the main boot process. By isolating the signature verification logic and storing public keys in a separate memory region, the system achieves reliable validation without unnecessarily complicating the overall device architecture.

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If write-protected region with golden boot image is implemented, then reliability is improved, but ease of operation deteriorates due to restricted write access

Engineering Contradiction:

Improvetrustworthiness of boot codeVSAvoidease of boot code update

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The system performs preliminary validation of the boot code image signature against stored public keys before allowing the update to proceed. This preliminary security check ensures that only authenticated and untampered boot images are installed, resolving the contradiction by maintaining ease of operation while preventing tampering through advance verification.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A signature validation mechanism acts as an intermediary between the boot code update process and the actual installation. This intermediary layer verifies the authenticity of incoming boot images using cryptographic signatures and public keys, allowing updates to remain convenient while ensuring their integrity and preventing tampering.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20240406008A1Memory device with secure boot updates and self recovery

Publication Date: 2024.12.05 MICRON TECHNOLOGY INC

AI summary

The example embodiments relate to improvements in managing boot code images. In an embodiment, a device is disclosed comprising a memory device, the memory device including a storage array, the storage array comprising a first partition and a second partition, wherein the first partition comprises a writeable partition and the second partition comprises a write-protected partition; and a processor configured to: load a golden boot image from the second partition, display a boot prompt after loading the golden boot image, receive an update boot image, the update boot image including a signature, read a public key from the second partition, validate the signature using the public key, and replace a current boot image stored in the first partition with the update boot image.