Memory Error Injection Protection via Reference Datum Comparison
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Solution Overview
Problem
Existing methods for protecting integrated circuits, such as those in smart cards, fail to detect attacks that aim to alter data during the reading process, specifically through error injection techniques that do not change the memory content but affect the read path.
Innovation Solution
Implementing a method where a reference datum is read and compared with an expected value during each memory read cycle, with the memory entering an error mode and sending an error signal if the read datum differs, thereby ensuring data integrity during the reading process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reference datum is read and compared with an expected value during each memory read cycle, then the memory is protected against error injection attacks, but the reading cycle time increases
Solution Approach 1:
The reference datum is read in advance during the same clock cycle as the main datum, before the comparison operation. This preliminary reading action allows the integrity check to be performed without extending the overall reading cycle time, as both readings occur in parallel during the same time period
Solution Approach 2:
The reading of the reference datum and the main datum is merged into a single clock cycle operation. By combining these two reading operations that would traditionally occur sequentially into one simultaneous operation, the patent eliminates the time penalty that would otherwise be incurred by adding an extra reading step
2Loss of time
If a reference datum is read during the same clock cycle as the main datum, then the protection mechanism does not increase reading cycle time, but the complexity of the memory reading mechanism increases
Solution Approach 1:
The existing memory reading mechanism is made multi-functional by enabling it to simultaneously read both the main datum and the reference datum during the same clock cycle. This universal reading capability allows the same hardware infrastructure to perform multiple functions without requiring separate dedicated reading circuits for each datum type
Solution Approach 2:
A comparison mechanism acts as an intermediary that receives both the main datum and reference datum from the memory array and determines whether they match. This intermediary component coordinates the simultaneous reading operations and generates the appropriate output signals without requiring complex control logic
Data Source
AI summary
A memory is secured against an error injection during the reading of a datum. The memory includes: means for reading a reference datum in the memory during a phase of reading a datum stored in the memory; means for comparing the reference datum read with an expected value; and means for generating an error signal if the datum read is different from the expected value. Application is provided particularly but not exclusively to the protection of memories integrated into smart cards.