Differential Fault Attacks on TFHE-Friendly Cipher FRAST
Summary
Researchers discovered that FRAST, a cipher designed to work efficiently with TFHE (Torus-based Fully Homomorphic Encryption, a method for computing on encrypted data), is vulnerable to differential fault attacks (DFAs, where attackers deliberately introduce errors into a system to extract secret keys). The attack can recover the encryption key in seconds using just a few faults, making it the first successful fault-based attack against this cipher.
Solution / Mitigation
The source recommends two countermeasures: 'removing the negacyclic restriction in the penultimate round of FRAST and introducing non-zero linear structures into the S-boxes (substitution boxes, which scramble data) of the last two rounds.' The source notes that standard linear structures cannot be added to negacyclic S-boxes without breaking their efficiency in TFHE.
Classification
Original source: http://ieeexplore.ieee.org/document/11659578
First tracked: August 31, 2026 at 08:03 PM
Classified by LLM (prompt v3) · confidence: 75%