Linear threshold multisecret sharing schemes

  • Authors:
  • Oriol FarríS;Ignacio Gracia;Sebastií MartíN;Carles Padró

  • Affiliations:
  • Dept. dEng. Informítica i Matemítiques, Universitat Rovira i Virgili, Tarragona, Spain;Dept. de Matemítica Aplicada IV, Universitat Politècnica de Catalunya, Barcelona, Spain;Dept. de Matemítica Aplicada IV, Universitat Politècnica de Catalunya, Barcelona, Spain;School of Mathematical Sciences, Nanyang Technological University, Singapore

  • Venue:
  • Information Processing Letters
  • Year:
  • 2012

Quantified Score

Hi-index 0.89

Visualization

Abstract

In a multisecret sharing scheme, several secret values are distributed among a set of n users, and each secret may have a different associated access structure. We consider here information-theoretic secure schemes with multithreshold access structures. Namely, for every subset P of k users there is a secret key that can only be computed when at least t of them put together their secret information. Coalitions with at most w users with less than t of them in P cannot obtain any information about the secret associated to P. The main parameters to optimize are the length of the shares and the amount of random bits that are needed to set up the distribution of shares, both in relation to the length of the secret. In this paper, we provide lower bounds on this parameters. Moreover, we present an optimal construction for t=2 and k=3.