Electromagnetic and Power Side-Channel Analysis: Advanced Attacks and Low-Overhead Generic Countermeasures through White-Box Approach

• Main Authors: Debayan Das, Shreyas Sen
• Format: Article
• Language: English
• Published: MDPI AG 2020-10-01
• Series: Cryptography
• Subjects: power/EM side-channel analysis attack; current domain signature attenuation hardware; low-overhead; deep-learning attack; <i>STELLAR</i>; <i>SCNIFFER</i>
• Online Access: https://www.mdpi.com/2410-387X/4/4/30

Electromagnetic and power side-channel analysis (SCA) provides attackers a prominent tool to extract the secret key from the cryptographic engine. In this article, we present our cross-device deep learning (DL)-based side-channel attack (<i>X-DeepSCA</i>) which reduces the time to attack on embedded devices, thereby increasing the threat surface significantly. Consequently, with the knowledge of such advanced attacks, we performed a ground-up white-box analysis of the crypto IC to root-cause the source of the electromagnetic (EM) side-channel leakage. Equipped with the understanding that the higher-level metals significantly contribute to the EM leakage, we present <i>STELLAR</i>, which proposes to route the crypto core within the lower metals and then embed it within a current-domain signature attenuation (CDSA) hardware to ensure that the critical correlated signature gets suppressed before it reaches the top-level metal layers. CDSA-AES256 with local lower metal routing was fabricated in a TSMC 65 nm process and evaluated against different profiled and non-profiled attacks, showing protection beyond <inline-formula><math display="inline"><semantics><mrow><mn>1</mn><mi>B</mi></mrow></semantics></math></inline-formula> encryptions, compared to ∼<inline-formula><math display="inline"><semantics><mrow><mn>10</mn><mi>K</mi></mrow></semantics></math></inline-formula> for the unprotected AES. Overall, the presented countermeasure achieved a <inline-formula><math display="inline"><semantics><mrow><mn>100</mn><mo>×</mo></mrow></semantics></math></inline-formula> improvement over the state-of-the-art countermeasures available, with comparable power/area overheads and without any performance degradation. Moreover, it is a generic countermeasure and can be used to protect any crypto cores while preserving the legacy of the existing implementations.