1,703 research outputs found
An Epitome of Multi Secret Sharing Schemes for General Access Structure
Secret sharing schemes are widely used now a days in various applications,
which need more security, trust and reliability. In secret sharing scheme, the
secret is divided among the participants and only authorized set of
participants can recover the secret by combining their shares. The authorized
set of participants are called access structure of the scheme. In Multi-Secret
Sharing Scheme (MSSS), k different secrets are distributed among the
participants, each one according to an access structure. Multi-secret sharing
schemes have been studied extensively by the cryptographic community. Number of
schemes are proposed for the threshold multi-secret sharing and multi-secret
sharing according to generalized access structure with various features. In
this survey we explore the important constructions of multi-secret sharing for
the generalized access structure with their merits and demerits. The features
like whether shares can be reused, participants can be enrolled or dis-enrolled
efficiently, whether shares have to modified in the renewal phase etc., are
considered for the evaluation
Fourier-based Function Secret Sharing with General Access Structure
Function secret sharing (FSS) scheme is a mechanism that calculates a
function f(x) for x in {0,1}^n which is shared among p parties, by using
distributed functions f_i:{0,1}^n -> G, where G is an Abelian group, while the
function f:{0,1}^n -> G is kept secret to the parties. Ohsawa et al. in 2017
observed that any function f can be described as a linear combination of the
basis functions by regarding the function space as a vector space of dimension
2^n and gave new FSS schemes based on the Fourier basis. All existing FSS
schemes are of (p,p)-threshold type. That is, to compute f(x), we have to
collect f_i(x) for all the distributed functions. In this paper, as in the
secret sharing schemes, we consider FSS schemes with any general access
structure. To do this, we observe that Fourier-based FSS schemes by Ohsawa et
al. are compatible with linear secret sharing scheme. By incorporating the
techniques of linear secret sharing with any general access structure into the
Fourier-based FSS schemes, we show Fourier-based FSS schemes with any general
access structure.Comment: 12 page
Secret Sharing Based on a Hard-on-Average Problem
The main goal of this work is to propose the design of secret sharing schemes
based on hard-on-average problems. It includes the description of a new
multiparty protocol whose main application is key management in networks. Its
unconditionally perfect security relies on a discrete mathematics problem
classiffied as DistNP-Complete under the average-case analysis, the so-called
Distributional Matrix Representability Problem. Thanks to the use of the search
version of the mentioned decision problem, the security of the proposed scheme
is guaranteed. Although several secret sharing schemes connected with
combinatorial structures may be found in the bibliography, the main
contribution of this work is the proposal of a new secret sharing scheme based
on a hard-on-average problem, which allows to enlarge the set of tools for
designing more secure cryptographic applications
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
Society-oriented cryptographic techniques for information protection
Groups play an important role in our modern world. They are more reliable and more trustworthy than individuals. This is the reason why, in an organisation, crucial decisions are left to a group of people rather than to an individual. Cryptography supports group activity by offering a wide range of cryptographic operations which can only be successfully executed if a well-defined group of people agrees to co-operate. This thesis looks at two fundamental cryptographic tools that are useful for the management of secret information. The first part looks in detail at secret sharing schemes. The second part focuses on society-oriented cryptographic systems, which are the application of secret sharing schemes in cryptography. The outline of thesis is as follows
Quantum cryptography: key distribution and beyond
Uniquely among the sciences, quantum cryptography has driven both
foundational research as well as practical real-life applications. We review
the progress of quantum cryptography in the last decade, covering quantum key
distribution and other applications.Comment: It's a review on quantum cryptography and it is not restricted to QK
Digital certificates and threshold cryptography
This dissertation discusses the use of secret sharing cryptographic protocols for distributing and sharing of secret documents, in our case PDF documents.
We discuss the advantages and uses of such a system in the context of collaborative environments.
Description of the cryptographic protocol involved and the necessary Public Key Infrastructure (PKI) shall be presented. We also provide an implementation of this framework as a “proof of concept” and fundament the use of a certificate extension as the basis for threshold cryptography.
Details of the shared secret distribution protocol and shared secret recovery protocol shall be given as well as the associated technical implementation details.
The actual secret sharing algorithm implemented at this stage is based on an existing well known secret sharing scheme that uses polynomial interpolation over a finite field.
Finally we conclude with a practical assessment of our prototype
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