Efuse Bank Anchor Bits for EMFI Attack Detection
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Solution Overview
Problem
Electronic systems employing one-time programmable (OTP) circuits are vulnerable to electromagnetic fault injection (EMFI) attacks, which can corrupt data and bypass security measures by altering logic values, compromising system security.
Innovation Solution
A circuit arrangement incorporating a bank of efuse cells, sense amplifiers, an efuse control circuit, and an efuse security circuit, utilizing anchor bits with constant logic-1 and logic-0 values to detect and alert on security violations, thereby preventing EMFI attacks by asserting an alert signal when invalid states are detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If OTP circuits are used to establish static configuration data for security features, then system security customization is enabled, but the circuits become vulnerable to electromagnetic fault injection attacks that can corrupt data and bypass security
Solution Approach 1:
The patent introduces anchor bits with predetermined known values that are established before the system operates. These anchor bits serve as reference points to detect whether EMFI attacks have corrupted the OTP circuit data. By having pre-established reference values, the system can proactively identify attacks rather than reactively responding to security breaches.
Solution Approach 2:
The patent implements a feedback mechanism where the system continuously monitors the anchor bit values and compares them against expected predetermined values. When a discrepancy is detected, the system generates an alert signal indicating a security violation. This closed-loop feedback enables real-time detection and response to EMFI attacks on the OTP circuits.
2Ease of operation
If sense amplifiers are used to read OTP circuit signals, then data reading is enabled, but the sensed signals can be intentionally disturbed by electromagnetic fault injection to alter logic values
Solution Approach 1:
The patent introduces anchor bits as intermediary reference elements between the sense amplifiers and the security verification system. These anchor bits provide known reference values that mediate the verification process, allowing the system to detect whether sense amplifier outputs have been corrupted by EMFI attacks. The anchor bits act as a trusted reference that bridges the gap between data reading and security verification.
3Device complexity
If no detection mechanism is implemented, then the circuit operation is simple, but security violations cannot be detected and unauthorized access can occur
Solution Approach 1:
The patent applies local quality by introducing anchor bits at specific locations within the OTP circuit structure. Rather than complicating the entire circuit, the solution places targeted detection elements (anchor bits with known values) at strategic positions where they can effectively monitor for EMFI attacks. This localized approach adds minimal complexity while providing effective security verification.
Data Source
AI summary
A disclosed circuit arrangement includes a bank of efuse cells, first and second sense amplifiers coupled to input signals representing constant logic-1 and logic-0 values, respectively, a storage circuit, an efuse control circuit, and an efuse security circuit. The efuse control circuit inputs signals from the bank of efuse cells and signals that are output from the first and second sense amplifiers, and stores data representative of values of the signals in the storage circuit. The efuse security reads the data from the storage circuit and generates an alert signal having a state that indicates a security violation in response to data representative of the value of the signal from the first sense amplifier indicating a logic-0 value or data representative of the value of the signal from the second sense amplifier indicating a logic-1 value.