Paper 2022/229

WiP: Applicability of ISO Standard Side-Channel Leakage Tests to NIST Post-Quantum Cryptography

Markku-Juhani O. Saarinen

Abstract

FIPS 140-3 is the main standard defining security requirements for cryptographic modules in U.S. and Canada; commercially viable hardware modules generally need to be compliant with it. The scope of FIPS 140-3 will also expand to the new NIST Post-Quantum Cryptography (PQC) standards when migration from older RSA and Elliptic Curve cryptography begins. FIPS 140-3 mandates the testing of the effectiveness of ``non-invasive attack mitigations'', or side-channel attack countermeasures. At higher security levels 3 and 4, the FIPS 140-3 side-channel testing methods and metrics are expected to be those of ISO 17825, which is based on the older Test Vector Leakage Assessment (TVLA) methodology. We discuss how to apply ISO 17825 to hardware modules that implement lattice-based PQC standards for public-key cryptography -- Key Encapsulation Mechanisms (KEMs) and Digital Signatures. We find that simple ``random key'' vs. ``fixed key'' tests are unsatisfactory due to the close linkage between public and private components of PQC keypairs. While the general statistical testing approach and requirements can remain consistent with older public-key algorithms, a non-trivial challenge in creating ISO 17825 testing procedures for PQC is the careful design of test vector inputs so that only relevant Critical Security Parameter (CSP) leakage is captured in power, electromagnetic, and timing measurements.

Note: A slightly expanded version of the Work-in-Progress report is to appear at the IEEE International Symposium on Hardware Oriented Security and Trust (HOST 2022) June 27 - 30, 2022, Washington DC, USA. http://www.hostsymposium.org/