Filianore: Better Multiplier Architectures For LWE-Based Post-Quantum Key Exchange

The (ring) learning with errors (RLWE/LWE) problem is one of the most promising candidates for constructing quantum-secure key exchange protocols. In this work, we design and implement specialized hardware multiplier units for both LWE and RLWE key exchange schemes to maximize their computational efficiency. By exploiting the algebraic structure with aggressive parameter sets, we show that the design and implementation of LWE key exchange on hardware is considerably easier and more flexible than RLWE. Using the proposed architectures, we show that client-side energy-efficiency of LWE-based key exchange can be on the same order, or even (slightly) better than RLWE-based schemes, making LWE an attractive option for designing post-quantum cryptographic suite.