Now showing items 1-9 of 9

    • Extending Brickell-Davenport theorem to non-perfect secret sharing schemes 

      Farràs Ventura, Oriol; Padró Laimon, Carles (2015-02)
      Article
      Open Access
      One important result in secret sharing is the Brickell-Davenport Theorem: every ideal perfect secret sharing scheme de nes a matroid that is uniquely determined by the access structure. Even though a few attempts have been ...
    • Ideal hierarchical secret sharing schemes 

      Farràs Ventura, Oriol; Padró Laimon, Carles (Springer, 2010)
      Conference report
      Open Access
      Hierarchical secret sharing is among the most natural generalizations of threshold secret sharing, and it has attracted a lot of attention from the invention of secret sharing until nowadays. Several constructions of ideal ...
    • Ideal hierarchical secret sharing schemes 

      Farràs Ventura, Oriol; Padró Laimon, Carles (2012-01-24)
      Article
      Open Access
      Hierarchical secret sharing is among the most natural generalizations of threshold secret sharing, and it has attracted a lot of attention since the invention of secret sharing until nowadays. Several constructions of ideal ...
    • Improving the linear programming technique in the search for lower bounds in secret sharing 

      Farràs Ventura, Oriol; Kaced, Tarik; Martín Mollevi, Sebastià; Padró Laimon, Carles (2020-11)
      Article
      Restricted access - publisher's policy
      We present a new improvement in the linear programming technique to derive lower bounds on the information ratio of secret sharing schemes. We obtain non-Shannon-type bounds without using information inequalities explicitly. ...
    • Multipartite secret sharing schemes 

      Farràs Ventura, Oriol (Universitat Politècnica de Catalunya, 2010-07-27)
      Doctoral thesis
      Open Access
      This thesis is dedicated to the study of secret sharing schemes, which are cryptographic methods to share information in a secure way. The topics that are considered in the thesis are two of the main open problems in secret ...
    • Natural generalizations of threshold secret sharing 

      Farràs Ventura, Oriol; Padró Laimon, Carles; Xing, Chaoping; Yang, An (2014-01-14)
      Article
      Open Access
      We present new families of access structures that, similarly to the multilevel and compartmented access structures introduced in previous works, are natural generalizations of threshold secret sharing. Namely, they admit ...
    • On the information ratio of non-perfect secret sharing schemes 

      Farràs Ventura, Oriol; Hansen, Torben; Kaced, Tarik; Padró Laimon, Carles (2017-12-01)
      Article
      Open Access
      A secret sharing scheme is non-perfect if some subsets of players that cannot recover the secret value have partial information about it. The information ratio of a secret sharing scheme is the ratio between the maximum ...
    • On the optimization of bipartite secret sharing schemes 

      Farràs Ventura, Oriol; Metcalf-Burton, Jessica Ruth; Padró Laimon, Carles; Vázquez González, Leonor (2012-05-01)
      Article
      Open Access
      Optimizing the ratio between the maximum length of the shares and the length of the secret value in secret sharing schemes for general access structures is an extremely difficult and long-standing open problem. In this ...
    • Optimal non-perfect uniform secret sharing schemes 

      Farràs Ventura, Oriol; Hansen, Torben; Kaced, Tarik; Padró Laimon, Carles (Springer, 2014)
      Conference report
      Open Access
      A secret sharing scheme is non-perfect if some subsets of participants that cannot recover the secret value have partial information about it. The information ratio of a secret sharing scheme is the ratio between the maximum ...