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.

Verifiable symmetric searchable encryption for semi-honest-but-curious cloud servers

Abstract: Outsourcing data to cloud servers, while increasing service availability and reducing users' burden of managing data, inevitably brings in new concerns such as data privacy, since the server may be honest-but-curious. To mediate the conflicts between data usability and data privacy in such a scenario, research of searchable encryption is of increasing interest. Motivated by the fact that a cloud server, besides its curiosity, may be selfish in order to save its computation and/or download bandwidth, in this paper, we investigate the searchable encryption problem in the presence of a semi-honest-but-curious server, which may execute only a fraction of search operations honestly and return a fraction of search outcome honestly. To fight against this strongest adversary ever, a verifiable SSE (VSSE) scheme is proposed to offer verifiable searchability in additional to the data privacy, both of which are further confirmed by our rigorous security analysis. Besides, we treat the practicality/efficiency as a central requirement of a searchable encryption scheme. To demonstrate the lightweightness of our scheme, we implemented and tested the proposed VSSE on a laptop (serving as the server) and a mobile phone running Android 2.3.4 (serving as the end user). The experimental results optimistically suggest that the proposed scheme satisfies all of our design goals.

New Publicly Verifiable Databases with Efficient Updates

Abstract: The notion of verifiable database (VDB) enables a resource-constrained client to securely outsource a very large database to an untrusted server so that it could later retrieve a database record and update it by assigning a new value. Also, any attempt by the server to tamper with the data will be detected by the client. Very recently, Catalano and Fiore [17] proposed an elegant framework to build efficient VDB that supports public verifiability from a new primitive named vector commitment. In this paper, we point out Catalano-Fiore’s VDB framework from vector commitment is vulnerable to the so-called forward automatic update (FAU) attack. Besides, we propose a new VDB framework from vector commitment based on the idea of commitment binding. The construction is not only public verifiable but also secure under the FAU attack. Furthermore, we prove that our construction can achieve the desired security properties.

A Signcryption Scheme with Signature Directly Verifiable by Public Key

Abstract: Signcryption, first proposed by Zheng [4, 5], is a cryptographic primitive which combines both the functions of digital signature and public key encryption in a logical single step, and with a computational cost siginficantly lower than that needed by the traditional signature-then-encryption approach. In Zheng's scheme, the signature verification can be done either by the recipient directly (using his private key) or by engaging a zero-knowledge interative protocol with a third party, without disclosing recipient's private key. In this note, we modify Zheng's scheme so that the recipient's private key is no longer needed in signature verification. The computational cost of the modified scheme is higher than that of Zheng's scheme but lower than that of the signature-then-encryption approach.

Efficient forward and provably secure ID-based signcryption scheme with public verifiability and public ciphertext authenticity

Abstract: Boyen [7] gave the first identity-based (ID-based) signcryption scheme that is forward secure, publicly verifiable as well as provably secure. However, his scheme aims at providing ciphertext unlinkability and anonymity which is not a desirable property in applications such as authentication of encrypted messages by firewalls [11], where any third party should be able to verify the origin of the ciphertext without knowing the content of the message and getting any help from the intended recipient. This requirement is referred as public ciphertext authenticity. In this paper, we give another ID-based signcryption scheme that can provide public ciphertext authenticity and is forward and provably secure as well as publicly verifiable. Our scheme is modified from Libert and Quisquater's ID-based signcryption scheme [16] and the efficiency of our scheme is comparable to other previous ID-based signcryption schemes.