Single-bit DFA using multiple-byte laser fault injection

Abstract

Laser fault injection is known as a fault attack method on cryptographic systems. This work provides practical experiments on an 8-bit 0.35μm microcontroller with no countermeasures. It explains how, with a laser beam that creates multiple-byte faults, it is still possible to perform single-bit/byte Differential Fault Analysis (DFA). It requires spatial and temporal adjustments for laser shooting and faulty results classification. This underlines the need to protect cryptographic devices, such as biometric passports and smart cards against surgical faults targeting one or several single-bits on specific bytes in memory.