Integrated Circuit Access Control Using Security Key Comparison
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Solution Overview
Problem
Existing integrated circuit access methods are inadequate in preventing unauthorized modifications, particularly the uninitialized state which allows full access, and rely on tamper detection circuits that may not be reliable.
Innovation Solution
An integrated circuit with a memory unit, a storage unit for a security key, a comparator unit, and an access control unit that compares security keys to grant access only when they match, and enables memory erasure if they do not, ensuring proper initialization by storing a valid security key.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the integrated circuit is in an uninitialized state to allow full access for testing purposes, then ease of operation is improved, but security is worsened due to vulnerability to tampering
Solution Approach 1:
The patent applies preliminary action by performing a security key comparison before granting full access to the integrated circuit. The processor compares a first security key stored in unalterable memory with a second security key stored in alterable memory before allowing testing operations, thereby preventing tampering while maintaining ease of operation for legitimate testing purposes
Solution Approach 2:
The patent uses an intermediary mechanism (security key comparison) between the uninitialized state and full access. The comparator unit and processor act as intermediaries that verify the integrity of security keys before permitting access, thus resolving the contradiction between ease of operation and security
2Reliability
If tamper detection circuits are used to prevent unauthorized modifications, then security is improved, but device complexity is worsened
Solution Approach 1:
The patent extracts the security verification function from a separate tamper detection circuit and integrates it into the existing processor and memory structure. By using the processor to compare security keys stored in existing memory units, the solution provides tamper detection without adding separate complex circuitry
Solution Approach 2:
The patent applies multi-functionality by using the existing processor and memory units for dual purposes: the processor handles both normal operations and security key comparison, while the memory units serve both data storage and security key storage functions, thereby providing tamper detection without increasing device complexity
3Adaptability or versatility
If security keys are stored in alterable memory to enable initialization, then adaptability is improved, but reliability is worsened due to potential corruption
Solution Approach 1:
The patent merges the security key storage functionality into the alterable memory unit, combining the benefits of adaptability (ability to initialize by writing security keys) with reliability (comparison against unalterable reference). The processor compares the alterable security key against the unalterable reference key to ensure integrity while maintaining initialization capability
Data Source
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AI summary
A method provides access to an integrated circuit which may comprise a storage containing an unalterable first security key and a memory containing a second security key. The method may comprise: - checking the second security key by comparing the first security key and the second security key, - if the second security key is valid, ∘ providing access to the integrated circuit, optionally depending on the validity of an access key, and - if the second security key is invalid, ∘ enabling erasing the memory, and ∘ storing in the memory a new second security key which corresponds to the first security key. Erasing the memory may be followed by checking the erasing for completeness.