A Novel Formula for Solving Quadratic Equations over Binary Extension Fields

Fuente: arXiv
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Main Authors: Yu, Leilei, Han, Yunghsiang S., Li, Pingping, Yuan, Jiasheng
Format: Preprint
Published: 2026
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author Yu, Leilei
Han, Yunghsiang S.
Li, Pingping
Yuan, Jiasheng
author_facet Yu, Leilei
Han, Yunghsiang S.
Li, Pingping
Yuan, Jiasheng
contents Solving quadratic equations over finite fields is a fundamental task in algebraic coding theory and serves as a key subroutine for computing the roots of cubic and quartic polynomials. Notably, any quadratic polynomial over binary extension fields can be transformed into the reduced form $x^2+x+c\in \mathbb{F}_{2^m}[x]$, for which existing formula-based methods rely on heavy exponentiation or case distinctions on $m$ (odd/even or powers of two), limiting uniformity and efficiency. This paper presents a unified, formula-based solution for all positive integers $m$ that uses only exclusive-OR operations (XORs). The approach leverages a Reed-Muller matrix characterization of evaluations and transforms the problem into computing a binary matrix-vector multiplication. The total cost is at most $m^2-2m+1$ XORs, and under parallelism, the latency is $\lceil \log_2 m\rceil$ XORs, making the method attractive for low-power, low-latency applications.
format Preprint
id arxiv_https___arxiv_org_abs_2601_01079
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A Novel Formula for Solving Quadratic Equations over Binary Extension Fields
Yu, Leilei
Han, Yunghsiang S.
Li, Pingping
Yuan, Jiasheng
Information Theory
Solving quadratic equations over finite fields is a fundamental task in algebraic coding theory and serves as a key subroutine for computing the roots of cubic and quartic polynomials. Notably, any quadratic polynomial over binary extension fields can be transformed into the reduced form $x^2+x+c\in \mathbb{F}_{2^m}[x]$, for which existing formula-based methods rely on heavy exponentiation or case distinctions on $m$ (odd/even or powers of two), limiting uniformity and efficiency. This paper presents a unified, formula-based solution for all positive integers $m$ that uses only exclusive-OR operations (XORs). The approach leverages a Reed-Muller matrix characterization of evaluations and transforms the problem into computing a binary matrix-vector multiplication. The total cost is at most $m^2-2m+1$ XORs, and under parallelism, the latency is $\lceil \log_2 m\rceil$ XORs, making the method attractive for low-power, low-latency applications.
title A Novel Formula for Solving Quadratic Equations over Binary Extension Fields
topic Information Theory
url https://arxiv.org/abs/2601.01079