Conference Paper

Simplified VSS and Fact-Track Multiparty Computations with Applications to Threshold Cryptography.

Source: DBLP
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    ABSTRACT: Privacy-preserving techniques for distributed computation have been proposed recently as a promising framework in collaborative inter-domain network monitoring. Several different approaches exist to solve such class of problems, e.g., Homomorphic Encryption (HE) and Secure Multiparty Computation (SMC) based on Shamir’s Secret Sharing algorithm (SSS). Such techniques are complete from a computation-theoretic perspective: given a set of private inputs, it is possible to perform arbitrary computation tasks without revealing any of the intermediate results. In this paper we advocate the use of “elementary” (as opposite to “complete“) Secure Multiparty Computation (E-SMC) procedures for traffic monitoring. E-SMC supports only simple computations with private input and public output, i.e., they can not handle secret input nor secret (intermediate) output. The proposed simplification brings a dramatic reduction in complexity and enables massive-scale implementation with acceptable delay and overhead. Notwithstanding their simplicity, we claim that a simple additive E-SMC scheme is sufficient to perform many computation tasks of practical relevance to collaborative network monitoring, such as anonymous publishing and set operations.
    Traffic Monitoring and Analysis - Third International Workshop, TMA 2011, Vienna, Austria, April 27, 2011. Proceedings; 01/2011
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    ABSTRACT: Privacy-preserving set operations and set intersection in particular are a popular research topic. Despite a large body of literature, the great majority of the available solutions are two-party protocols and are not composable. In this work we design a comprehensive suite of secure multi-party protocols for set and multiset operations that are composable, do not assume any knowledge of the sets by the parties carrying out the secure computation, and can be used for secure outsourcing. All of our protocols have communication and computation complexity of O(m log m) for sets or multisets of size m, which compares favorably with prior work. Furthermore, we are not aware of any results that realize composable operations. Our protocols are secure in the information theoretic sense and are designed to minimize the round complexity.
    IACR Cryptology ePrint Archive. 01/2011; 2011:464.
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    ABSTRACT: At CHES 2011 Goubin and Martinelli described a new countermeasure against side-channel analysis for AES based on Shamir's secret-sharing scheme. In the present paper, we exhibit a flaw in this scheme and we show that it is always theoretically broken by a first-order side-channel analysis. As a consequence of this attack, only a slight adaptation of the scheme proposed by Ben-Or et STOC in 1988 can securely process multiplications on data shared with Shamir's technique. In the second part of this paper, we propose an improvement of this scheme that leads to a complexity ${\cal \tilde O}(d^2)$ instead of ${\cal O}(d^3)$, where d is the number of shares per data.
    Proceedings of the 11th international conference on Smart Card Research and Advanced Applications; 11/2012