25.3 A 128b AES Engine with Higher Resistance to Power and Electromagnetic Side-Channel Attacks Enabled by a Security-Aware Integrated All-Digital Low-Dropout Regulator

Abstract

Side channel attacks (SCA) exploit data-dependent information leakage through power consumption and electromagnetic (EM) emissions from cryptographic engines to uncover secret keys. Integrated inductive voltage regulators (IVR) with a randomized control loop [1] or switching frequency [2], and random voltage dithering [3] have demonstrated improved power side-channel analysis (PSCA) resistance. Simulation studies have shown PSCA resistance via shunt linear regulators [4]. This paper demonstrates improved power and EM SCA resistance of standard (unprotected) 128b AES engines with parallel (P-AES, 128b) and serial (S-AES, 8b) datapaths via an on-die security-aware all-digital series low-dropout (DLDO) regulator, commonly used for fine-grain SoC power management. The security-aware DLDO improves SCA resistance using control-loop induced perturbations in a baseline DLDO, enhanced by a random switching noise injector (SNI) via power stage control and a randomized reference voltage (R-VREF) generator coupled with all-digital clock modulation (ADCM).