In this paper we propose an optimistic two-party fair exchange protocol which does not rely on a centralized trusted third party. Instead, the fairness of the protocol relies on the honesty of part of the neighbor participants. This new concept, which is based on a generic verifiable secret sharing scheme, is particularly relevant in networks where centralized authority can neither be used on-l...

In this paper, we introduce a new efficient technique allowing to render an off-line e-cash system traceable without need to a trusted party. The main idea is the use of the publicly verifiable secret sharing technique in order to revoke the anonymity of double spending users. The anonymity of honest users is still provided. Security analysis shows that the proposed technique does not undermine...

A multi-secret sharing scheme (MSS) allows a dealer to share multiple secrets among a set of participants. in such a way a multi-secret sharing scheme (MSS) allows a dealer to share multiple secrets among a set of participants, such that any authorized subset of participants can reconstruct the secrets. Up to now, existing MSSs either require too long shares for participants to be perfect secur...

This paper studies the methods for changing thresholds in the absence of secure channels after the setup of threshold secret sharing schemes. First, we construct a perfect (t, n) threshold scheme that is threshold changeable to t ′ > t , which is optimal with respect to the share size. This improves the scheme of Wang and Wong by relaxing the requirement from q ≥ n + v to q > n with the secret-...

In this paper a secret sharing scheme based on the word problem in groups is introduced. The security of the scheme and possible variations are discussed in section 2. The article concludes with the suggestion of two categories of platform groups for the implementation of the scheme.

We prove that for d > 1 the information rate of the perfect secret sharing scheme based on the edge set of the d-dimensional cube is exactly 2/d. Using the technique developed, we also prove that the information rate of the infinite d-dimensional lattice is 1/d.

In combinatorial group testing problems Questioner needs to find a defective element x ∈ [n] by testing subsets of [n]. In [18] the authors introduced a new model, where each element knows the answer for those queries that contain it and each element should be able to identify the defective one. In this article we continue to investigate this kind of models with more defective elements. We also...