A New Algorithm for Solving Ring-LPN with a Reducible Polynomial
This work addresses a specific cryptographic vulnerability for protocols relying on reducible polynomials, representing an incremental improvement in cryptanalysis.
The authors tackled the RING-LPN problem with reducible polynomials by developing a new algorithm that significantly outperforms previous methods, enabling the breaking of the Lapin authentication protocol in about 2^70 bit operations.
The LPN (Learning Parity with Noise) problem has recently proved to be of great importance in cryptology. A special and very useful case is the RING-LPN problem, which typically provides improved efficiency in the constructed cryptographic primitive. We present a new algorithm for solving the RING-LPN problem in the case when the polynomial used is reducible. It greatly outperforms previous algorithms for solving this problem. Using the algorithm, we can break the Lapin authentication protocol for the proposed instance using a reducible polynomial, in about 2^70 bit operations.