Verifiable secret sharing

About: Verifiable secret sharing is a research topic. Over the lifetime, 4241 publications have been published within this topic receiving 99569 citations.

Secret sharing schemes with three or four minimal qualified subsets

Abstract: In this paper we study secret sharing schemes whose access structure has three or four minimal qualified subsets. The ideal case is completely characterized and for the non-ideal case we provide bounds on the optimal information rate.

Authenticated ID-based cryptosystem with no key escrow

Abstract: A method and system are provided for determining a shared secret between two entities in a cryptosystem. A first random secret is selected that is known to the first entity and unknown to the second entity. A first intermediate shared secret component is determined using the first random secret and a system parameter. The first intermediate shared secret component is communicated to the second entity. A second random secret is selected that is known to the second entity, but unknown to the first entity. A second intermediate shared secret component is determined using the second random secret and the system parameter. The second intermediate shared secret component is communicated to the first entity. It is confirmed that both the first entity and the second entity know a non-interactive shared secret. An interactive shared secret is determined using the first random secret, the second random secret, and the system parameter.

Beyond provable security verifiable IND-CCA security of OAEP

Abstract: OAEP is a widely used public-key encryption scheme based on trapdoor permutations. Its security proof has been scrutinized and amended repeatedly. Fifteen years after the introduction of OAEP, we present a machine-checked proof of its security against adaptive chosenciphertext attacks under the assumption that the underlying permutation is partial-domain one-way. The proof can be independently verified by running a small and trustworthy proof checker and fixes minor glitches that have subsisted in published proofs. We provide an overview of the proof, highlight the differences with earlier works, and explain in some detail a crucial step in the reduction: the elimination of indirect queries made by the adversary to random oracles via the decryption oracle. We also provide--within the limits of a conference paper--a broader perspective on independently verifiable security proofs.

Multi-tasking, quality and pay for performance.

Abstract: We present a model of optimal contracting between a purchaser and a provider of health services when quality has two dimensions. We assume that: (i) the provider is (at least to some extent) altruistic; (ii) one dimension of quality is verifiable (dimension 1) and one dimension is not verifiable (dimension 2); (iii) the two quality dimensions can be either substitutes or complements. Our main result is that setting the price equal to the marginal benefit of the verifiable quality dimension can be optimal even if the two quality dimensions are substitutes.

Verifiable Oblivious Storage.

Abstract: We formalize the notion of Verifiable Oblivious Storage (VOS), where a client outsources the storage of data to a server while ensuring data confidentiality, access pattern privacy, and integrity and freshness of data accesses. VOS generalizes the notion of Oblivious RAM (ORAM) in that it allows the server to perform computation, and also explicitly considers data integrity and freshness. We show that allowing server-side computation enables us to construct asymptotically more efficient VOS schemes whose bandwidth overhead cannot be matched by any ORAM scheme, due to a known lower bound by Goldreich and Ostrovsky. Specifically, for large block sizes we can construct a VOS scheme with constant bandwidth per query; further, answering queries requires only poly-logarithmic server computation. We describe applications of VOS to Dynamic Proofs of Retrievability, and RAM-model secure multi-party computation.