5 research outputs found
On the bound for anonymous secret sharing schemes
AbstractIn anonymous secret sharing schemes, the secret can be reconstructed without knowledge of which participants hold which shares. In this paper, we derive a tighter lower bound on the size of the shares than the bound of Blundo and Stinson for anonymous (k,n)-threshold schemes with 1<k<n. Our bound is tight for k=2. We also show a close relationship between optimum anonymous (2,n)-threshold secret schemes and combinatorial designs
Access Structure Hiding Secret Sharing from Novel Set Systems and Vector Families
Secret sharing provides a means to distribute shares of a secret such that
any authorized subset of shares, specified by an access structure, can be
pooled together to recompute the secret. The standard secret sharing model
requires public access structures, which violates privacy and facilitates the
adversary by revealing high-value targets. In this paper, we address this
shortcoming by introducing \emph{hidden access structures}, which remain secret
until some authorized subset of parties collaborate. The central piece of this
work is the construction of a set-system with strictly greater
than subsets of a set
of elements. Our set-system is defined over ,
where is a non-prime-power, such that the size of each set in
is divisible by but the sizes of their pairwise intersections are not
divisible by , unless one set is a subset of another. We derive a vector
family from such that superset-subset relationships
in are represented by inner products in . We use
to "encode" the access structures and thereby develop the first
\emph{access structure hiding} secret sharing scheme. For a setting with
parties, our scheme supports out of the
total monotone access structures, and its maximum
share size for any access structures is . The scheme assumes semi-honest polynomial-time parties, and its
security relies on the Generalized Diffie-Hellman assumption.Comment: This is the full version of the paper that appears in D. Kim et al.
(Eds.): COCOON 2020 (The 26th International Computing and Combinatorics
Conference), LNCS 12273, pp. 246-261. This version contains tighter bounds on
the maximum share size, and the total number of access structures supporte
Anonymous threshold signatures
Aquest treball tenia l'objectiu de trobar un esquema de llindar de signatura an\`onima compacte. Tot i no haver-ne trobat cap, s'analitzen diverses solucions que s'acosten a l'objectiu publicades per altres autors i es proposa una millora per obtenir un esquema com el desitjat, però costós i interactiu
Secret sharing using artificial neural network
Secret sharing is a fundamental notion for secure cryptographic design. In a secret sharing scheme, a set of participants shares a secret among them such that only pre-specified subsets of these shares can get together to recover the secret. This dissertation introduces a neural network approach to solve the problem of secret sharing for any given access structure. Other approaches have been used to solve this problem. However, the yet known approaches result in exponential increase in the amount of data that every participant need to keep. This amount is measured by the secret sharing scheme information rate. This work is intended to solve the problem with better information rate