Dependability analysis of a countermeasure against fault attacks by means of laser shots onto a SRAM-based FPGA

Laser-based fault injections are currently the most efficient technique that can be used to attack a secure system, since they have very high timing and location precision. Several papers have shown that a secret key may be recovered from ASICs and countermeasures have been proposed. But little research has been addressed at the specific case of secure protected implementations in SRAM-based FPGAs. This paper presents the results of laser-based fault injections on an architecture computing the AES encryption algorithm, protected by an error detection scheme, and implemented on a Virtex device. The results are compared to previous emulated fault injection campaigns and prove the criticality of remnant errors in the configuration of a FPGA used for secure applications. An improved countermeasure is also proposed and validated with a new experimental campaign.