January 25, 2023
Hemanta Maji - Purdue University
Abstract: Much research has gone into protecting cryptographic primitives from side-channel attacks. Shamir's secret-sharing scheme is one such primitive -- its security vulnerabilities may compromise (among others) nearly all threshold cryptography, access control, and secure storage & computation. This talk presents our work on assessing the threats to Shamir's secret-sharing scheme from local leakage attacks. Surprisingly, even leaking a small amount of information from all secret shares may compromise the secret. Our objective is to (1) recommend secure choices of the modulus and evaluation places and (2) identify vulnerabilities for insecure choices. In this talk, I will present (Monte Carlo and derandomized) constructions of the Shamir secret-sharing scheme secure against various families of local leakage attacks, including physical bit probing. To complement these results, I will also present novel local leakage attacks if the secret-sharing is insecurely instantiated.
Based on joint works with Hai H. Nguyen, Anat Paskin-Cherniavsky, Tom Suad, Mingyuan Wang, Xiuyu Ye, and Albert Yu appearing at CRYPTO 2021, EUROCRYPT 2021, ISIT 2021, TCC 2022, ISIT 2022, and ITC 2022.
Suggest readings: ia.cr/2020/1517, ia.cr/2021/186
