In information security, ignorance is not bliss. It is always stated that hiding the protocols (let the other be ignorant about it) does not increase the security of organizations. However, there are cases that ignorance creates protocols. In this paper, we propose distributed contingency logic, a proper extension of contingency (ignorance) logic. Intuitively, a formula is distributed contingen...

We would like to thank Shai Ben-David, Oded Goldreich and Hugo Krawczyk for helpful discussions on the topics of this paper. We would also like to thank Bob Blakley for acquainting us with his work 8, 9]. In this section we deal with secret-sharing schemes over the real numbers. Although it has no practical implications, it is interesting to ask the question whether secret-sharing schemes do no...

Visual Cryptography was first proposed by Moni Naor and Adi Shamir in Eurocrypt’94. They demonstrated a (t, n) visual secret sharing scheme, in which visual information is encoded into n shares so that only someone with t or more than t shares could decrypt this visual information, while nothing would be revealed by any t-1 shares. Particularly, the decryption is performed directly by stacking ...

We show a general connection between various types of statistical zero-knowledge (SZK) proof systems and (unconditionally secure) secret sharing schemes. Viewed through the SZK lens, we obtain several new results on secret-sharing: • Characterizations: We obtain an almost-characterization of access structures for which there are secret-sharing schemes with an efficient sharing algorithm (but no...

Based on a quantum secure direct communication (QSDC) protocol [Phys. Rev. A69(04)052319], we propose a (n, n)-threshold scheme of multiparty quantum secret sharing of classical messages (QSSCM) using only single photons. We take advantage of this multiparty QSSCM scheme to establish a scheme of multiparty secret sharing of quantum information (SSQI), in which only all quantum information recei...

A recent work of Harn and Fuyou presents the first multilevel (disjunctive) threshold secret sharing scheme based on the Chinese Remainder Theorem. In this work, we first show that the proposed method is not secure and also fails to work with a certain natural setting of the threshold values on compartments. We then propose a secure scheme that works for all threshold settings. In this scheme, ...

In traditional secret sharing schemes for general access structures, a secret can be encoded into n sets of (shadow, key)’s which are distributed to n participants one by one. Only those participants belonging to a pre-defined qualified subset can recover the shared secret by using their (shadow, key)’s. The size of (shadow, key)’s may be different for different participants. This problem exist...

A necessary and sufficient condition for the asymptotic idealness of the AsmuthBloom threshold secret sharing scheme is proposed. Apart from this, a comprehensive analysis of the known variants of the Asmuth-Bloom threshold secret sharing scheme is provided, clarifying the security properties achieved by each of them.

Traditionally, (k, n) secret image sharing is an approach of breaking down a secret image into n number of shadow images to assign them to n number of users, so that any k or more then k users can bring back the secret image. But in case of less than k, users cannot reveal any partial information about the original image. We have proposed a significant secret image sharing technique based on XO...