{"title":"(k, n)-Consecutive access structures","authors":"Javier Herranz, Germán Sáez","doi":"10.1007/s10623-025-01651-7","DOIUrl":null,"url":null,"abstract":"<p>We consider access structures over a set of <i>n</i> participants, defined by a parameter <i>k</i> with <span>\\(1 \\le k \\le n\\)</span> in the following way: a subset is authorized if it contains at least <i>k</i> consecutive participants. Depending on whether we consider the participants placed in a line (that is, participant 1 is not next to participant <i>n</i>) or in a circle, we obtain two different families, that we call (<i>k</i>, <i>n</i>)-line-consecutive and (<i>k</i>, <i>n</i>)-circle-consecutive access structures, respectively. Such access structures can appear in real-life situations involving distributed cryptography, which makes it more interesting to look for the best secret sharing schemes that can realize them. For both families, we characterize which are the configurations (<i>k</i>, <i>n</i>) that admit ideal secret sharing schemes. For the non-ideal (<i>k</i>, <i>n</i>)-consecutive access structures, we give both upper and lower bounds on the information ratio of the best secret sharing schemes that can realize them. Some of these bounds are obtained after proving relations between the information ratios of access structures in the two considered families.</p>","PeriodicalId":11130,"journal":{"name":"Designs, Codes and Cryptography","volume":"56 1","pages":""},"PeriodicalIF":1.2000,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Designs, Codes and Cryptography","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.1007/s10623-025-01651-7","RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"COMPUTER SCIENCE, THEORY & METHODS","Score":null,"Total":0}
引用次数: 0
Abstract
We consider access structures over a set of n participants, defined by a parameter k with \(1 \le k \le n\) in the following way: a subset is authorized if it contains at least k consecutive participants. Depending on whether we consider the participants placed in a line (that is, participant 1 is not next to participant n) or in a circle, we obtain two different families, that we call (k, n)-line-consecutive and (k, n)-circle-consecutive access structures, respectively. Such access structures can appear in real-life situations involving distributed cryptography, which makes it more interesting to look for the best secret sharing schemes that can realize them. For both families, we characterize which are the configurations (k, n) that admit ideal secret sharing schemes. For the non-ideal (k, n)-consecutive access structures, we give both upper and lower bounds on the information ratio of the best secret sharing schemes that can realize them. Some of these bounds are obtained after proving relations between the information ratios of access structures in the two considered families.
期刊介绍:
Designs, Codes and Cryptography is an archival peer-reviewed technical journal publishing original research papers in the designated areas. There is a great deal of activity in design theory, coding theory and cryptography, including a substantial amount of research which brings together more than one of the subjects. While many journals exist for each of the individual areas, few encourage the interaction of the disciplines.
The journal was founded to meet the needs of mathematicians, engineers and computer scientists working in these areas, whose interests extend beyond the bounds of any one of the individual disciplines. The journal provides a forum for high quality research in its three areas, with papers touching more than one of the areas especially welcome.
The journal also considers high quality submissions in the closely related areas of finite fields and finite geometries, which provide important tools for both the construction and the actual application of designs, codes and cryptographic systems. In particular, it includes (mostly theoretical) papers on computational aspects of finite fields. It also considers topics in sequence design, which frequently admit equivalent formulations in the journal’s main areas.
Designs, Codes and Cryptography is mathematically oriented, emphasizing the algebraic and geometric aspects of the areas it covers. The journal considers high quality papers of both a theoretical and a practical nature, provided they contain a substantial amount of mathematics.