Verifiable secret sharing (VSS) is an important primitive in distributed cryptography that allows a dealer to share a secret among n parties in the presence of an adversary controlling at most t of them. In the computational setting, the feasibility of VSS schemes based on commitments was established over two decades ago. Interestingly, all known computational VSS schemes rely on the homomorphi...

Verifiable Secret Sharing (VSS) guarantees that honest parties reconstruct a consistent secret even in the presence of a malicious dealer that distributes invalid shares. We empower the dishonest dealer and consider the case when he subliminally leaks information in valid shares, allowing an adversary to access the secret prior to the reconstruction phase. We define the concept of Dealer-Leakag...

We address the problem of performing a multiparty computation when more than half of the processors are cooperating Byzantine faults. We show how to compute any boolean function of n inputs distributively, preserving the privacy of inputs held by nonfaulty processors, and ensuring that faulty processors obtain the function value “if and only if” the nonfaulty processors do. If the nonfaulty pro...

We revisit the following question: what is the optimal round complexity of verifiable secret sharing (VSS)? We focus here on the case of perfectly-secure VSS where the number of corrupted parties t satisfies t < n/3, with n being the total number of parties. Work of Gennaro et al. (STOC 2001) and Fitzi et al. (TCC 2006) shows that, assuming a broadcast channel, 3 rounds are necessary and suffic...

Verifiable Secret-Sharing (VSS) is a fundamental primitive in secure distributed computing. It used as building block several computing tasks, such Byzantine agreement and multi-party computation. In this article, we consider VSS schemes with perfect security, tolerating computationally unbounded adversaries. We comprehensively survey the existing perfectly three different communication setting...

A Key Distribution Center of a network is a server enabling private communications within groups of users. A Distributed Key Distribution Center is a set of servers that jointly realizes a Key Distribution Center. In this paper we build a robust Distributed Key Distribution Center Scheme secure against active and mobile adversary. We consider a general access structure for the set of servers an...

This article proposes efficient solutions for the construction of sealed-bid second-price and combinatorial auction protocols in an active adversary setting. The main reason for constructing secure auction protocols is that the losing bids can be used in the future auctions as well as negotiations if they are not kept private. Our motivation is to apply verifiable secret sharing in order to con...