Minimal Linear Codes over Finite Fields

As a special class of linear codes, minimal linear codes have important applications in secret sharing and secure two-party computation. Constructing minimal linear codes with new and desirable parameters has been an interesting research topic in coding theory and cryptography. Ashikhmin and Barg showed that $w{\min}/w{\max}> (q-1)/q$ is a sufficient condition for a linear code over the finite field $\gf(q)$ to be minimal, where $q$ is a prime power, $w{\min}$ and $w{\max}$ denote the minimum and maximum nonzero weights in the code, respectively. The first objective of this paper is to present a sufficient and necessary condition for linear codes over finite fields to be minimal. The second objective of this paper is to construct an infinite family of ternary minimal linear codes satisfying $w{\min}/w{\max}\leq 2/3$. To the best of our knowledge, this is the first infinite family of nonbinary minimal linear codes violating Ashikhmin and Barg's condition.