Paper 2022/874 Original: eprint.iacr.org/2022/874 ↗

Lattice Codes for Lattice-Based PKE

Abstract

Existing error correction mechanisms in lattice-based public key encryption (PKE) rely on either trivial modulation or its concatenation with error correction codes (ECC). This paper demonstrates that lattice coding, as a combined ECC and modulation technique, can replace trivial modulation in current lattice-based PKEs, resulting in improved error correction performance. We model the FrodoPKE protocol as a noisy point-to-point communication system, where the communication channel resembles an additive white Gaussian noise (AWGN) channel. To utilize lattice codes for this specific channel with hypercube shaping, we propose an efficient labeling function that converts binary information bits to lattice codewords and vice versa. The parameter sets of FrodoPKE are enhanced to achieve higher security levels or smaller ciphertext sizes. For instance, the proposed Frodo-1344-E$_\text{8}$ offers a 10-bit classical security improvement over Frodo-1344. The code for reproducing our main experiments is available at https://github.com/shx-lyu/lattice-codes-for-pke.