Generalized Subspace Subcodes in the Rank Metric

TL;DR

This paper introduces a generalized family of subspace subcodes in the rank metric, providing algorithms for their construction, analyzing their properties, and establishing bounds on their sizes, with implications for coding security and diversity.

Contribution

It generalizes the concept of subspace subcodes in rank-metric codes and offers algorithms for their construction and analysis, expanding the landscape of rank-metric code families.

Findings

Provides a new generalization of subspace subcodes in rank metric

Develops algorithms for generator and parity-check matrices

Establishes bounds on code cardinalities

Abstract

Rank-metric codes were studied by E. Gabidulin in 1985 after a brief introduction by Delsarte in 1978 as an equivalent of Reed-Solomon codes, but based on linearized polynomials. They have found applications in many areas, including linear network coding and space-time coding. They are also used in cryptography to reduce the size of the keys compared to Hamming metric codes at the same level of security. However, some families of rank-metric codes suffer from structural attacks due to the strong algebraic structure from which they are defined. It therefore becomes interesting to find new code families in order to address these questions in the landscape of rank-metric codes. \par In this paper, we provide a generalization of Subspace Subcodes in Rank metric introduced by Gabidulin and Loidreau. We also characterize this family by giving an algorithm which allows to have its generator and parity-check matrices based on the associated extended codes. We have also studied the specific case of Gabidulin codes whose underlying decoding algorithms are known. Bounds for the cardinalities of these codes, both in the general case and in the case of Gabidulin codes, are also provided.