Zero-Knowledge Accumulators and Set Algebra
Zero-Knowledge Accumulators and Set Algebra
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DOI:
10.1007/978-3-662-53890-6_3
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发表时间:
2016-12
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影响因子:
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通讯作者:
Esha Ghosh;O. Ohrimenko;D. Papadopoulos;R. Tamassia;Nikos Triandopoulos
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作者:
Esha Ghosh;O. Ohrimenko;D. Papadopoulos;R. Tamassia;Nikos Triandopoulos
Cryptographic accumulators allow to succinctly represent a set by an accumulation value with respect to which short (non-)membership proofs about the set can be efficiently constructed and verified. Traditionally, their security captures soundness but offers no privacy: Convincing proofs reliably encode set membership, but they may well leak information about the accumulated set.In this paper we put forward a strong privacy-preserving enhancement by introducing and devisingzero-knowledge accumulatorsthat additionally provide hiding guarantees: Accumulation values and proofs leak nothing about a dynamic set that evolves via element insertions/deletions. We formalize the new property using the standard real-ideal paradigm, namely demanding that an adaptive adversary with access to query/update oracles, cannot tell whether he interacts with honest protocol executions or a simulator fully ignorant of the set (even of the type of updates on it). We rigorously compare the new primitive to existing ones for privacy-preserving verification of set membership (or other relations) and derive interesting implications among related security definitions, showing that zero-knowledge accumulators offer stronger privacy than recent related works by Naor et al. [TCC 2015] and Derler et al. [CT-RSA 2015]. We construct the first dynamic universal zero-knowledge accumulator that we show to be perfect zero-knowledge and secure under theq-Strong Bilinear Diffie-Hellman assumption.Finally, we extend our new privacy notion and our new construction to provide privacy-preserving proofs also for an authenticated dynamic set collection—a primitive for efficiently verifying more elaborate set operations, beyond set-membership. We introduce a primitive that supports azero-knowledge verifiable set algebra: Succinct proofs for union, intersection and set difference queries over a dynamically evolving collection of sets can be efficiently constructed and optimally verified, while—for the first time—they leak nothing about the collection beyond the query result.