Firmware Security Verification Using Digital Signatures
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Solution Overview
Problem
Existing firmware verification methods are inadequate in ensuring the security of firmware data, as they cannot detect malicious modifications, allowing third parties to tamper with firmware and CRC check results during transfer.
Innovation Solution
A firmware security verification device and method that acquires and verifies firmware data using a digital signature with a pre-stored public key, ensuring the signature's integrity through asymmetrical encryption and self-testing of the encryption algorithm, preventing unauthorized modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CRC check is used to verify firmware integrity, then data transfer errors can be detected, but malicious modifications to firmware and CRC results cannot be identified
Solution Approach 1:
The patent introduces a digital signature as an intermediary verification mechanism. Instead of directly verifying firmware integrity with simple CRC checks, a digital signature (generated by encrypting the firmware hash with a private key) serves as a mediator that proves the firmware's authenticity. The verification process uses the corresponding public key to decrypt and compare the signature, providing cryptographic proof that the firmware has not been maliciously modified.
Solution Approach 2:
The patent replaces the mechanical/CRC-based verification system with a cryptographic verification system. Instead of using simple checksum algorithms that can be easily bypassed, the system uses public key cryptography (asymmetric encryption) to create a verification mechanism that is computationally infeasible to forge, thereby substituting weak verification with strong cryptographic verification.
2Adaptability or versatility
If firmware is made rewritable for updates, then adaptability to hardware changes is improved, but vulnerability to malicious modification increases
Solution Approach 1:
The patent applies preliminary action by pre-generating and storing the public key in the firmware along with the digital signature before the firmware is written to the rewritable memory. This preliminary preparation ensures that when the firmware is later updated or modified through legitimate channels, the new firmware can be verified using the same pre-stored public key, maintaining security throughout the firmware's lifecycle despite the rewritable nature of the storage.
Solution Approach 2:
The patent implements a feedback mechanism where the verification result (whether the digital signature matches) provides immediate feedback on the firmware's integrity. If the verification fails, the system can reject the firmware update or alert the user, creating a feedback loop that prevents malicious modifications from being applied, thereby maintaining security while allowing legitimate updates.
Data Source
AI summary
The present disclosure relates to a firmware security verification method and device, including a processor and a read-only memory for storing instructions executable by the processor. While executing the instructions, the processor implements the following steps: acquiring firmware data and a digital signature; verifying the digital signature with a pre-stored public key; and running the firmware data upon determining that the digital signature passes the verification. With the firmware security verification method and device provided in embodiments of the present disclosure, the security of the firmware data can be acquired before the running of firmware.