IST Image Authentication Using Cached Final Hashes
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Solution Overview
Problem
Existing in-system test (IST) methods for integrated circuits (ICs), particularly in automotive applications, face challenges in achieving 90% test coverage within stringent Fault-Tolerant Time Interval (FTTI) requirements due to latency from block chain authentication (BCA) checks, which consume significant CPU resources and hinder functional operation.
Innovation Solution
The method involves storing final hashes of each block chain authentication (BCA) section in a write-protected memory, authenticating a single Public Key Authentication (PKA) signature, and using these hashes to authenticate IST image portions, thereby skipping individual PKA signature checks, and employing caching mechanisms to reduce latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If block chain authentication (BCA) checks are performed for test-data authentication, then data integrity and security are improved, but latency increases and CPU performance is reduced
Solution Approach 1:
The patent performs PKA signature checks in advance during the IST image loading phase before the actual RIST execution begins. By completing these authentication operations beforehand, the system eliminates the need for repeated PKA checks during runtime testing, thereby reducing latency while maintaining data integrity through preliminary verification of test data authenticity.
2Productivity
If RIST tests one processing core at a time to minimize performance impact, then functional operation is preserved, but test coverage time is reduced
Solution Approach 1:
The patent extracts and eliminates the PKA signature check operations from the runtime RIST execution path. By removing these time-consuming authentication checks from the test execution phase and performing them only during the initial IST image loading, the system recovers valuable CPU time for actual testing, thereby increasing test coverage speed without compromising functional operation.
3Reliability
If multiple PKA signature checks are performed for each BCA section, then authentication thoroughness is improved, but CPU overhead increases
Solution Approach 1:
The patent merges multiple PKA signature checks into a single authentication operation performed during the IST image loading phase. Instead of performing separate PKA checks for each BCA section during runtime, the system performs one comprehensive authentication operation that verifies all test data integrity, thereby reducing CPU overhead while maintaining authentication thoroughness through consolidated verification.
Data Source
AI summary
An integrated circuit (IC) is disclosed. In one embodiment, the IC comprises a memory and at least one processing core coupled to the memory. In one embodiment, the operations the at least one processing core operatively coupled to the memory perform comprise storing final hashes of each block chain authentication (BCA) section of an in-system test (IST) image in a write-protected portion of the memory; receiving at least one Public Key Authentication (PKA) signature; authenticating the at least one PKA signature using public key cryptography (PKC) algorithm; once the PKA signature is authenticated, using the final hash for each BCA section to authenticate a portion of the IST image associated with each BCA section using a hash engine of the at least one processing core skipping any PKA signature checks for any of the final hashes; and testing portions of the IC with the authenticated IST image portion.