-- In the plain model, assuming one-to-one one-way functions, we show how to obtain noisy-leakage-resilient continuous non-malleability for arbitrary access structures, in case the attacker can continuously leak from and tamper with all of the shares independently.
-- In the common reference string model, we show how to obtain a new flavor of security which we dub bounded-leakage-resilient continuous non-malleability under selective k-partitioning. In this model, the attacker is allowed to partition the target n shares into any number of non-overlapping blocks of maximal size k, and then can continuously leak from and tamper with the shares within each block jointly. Our construction works for arbitrary access structures, and assuming (doubly enhanced) trapdoor permutations and collision-resistant hash functions, we achieve a concrete instantiation for k = O(log(n)).
Prior to our work, there was no secret sharing scheme achieving continuous non-malleability against joint tampering, and the only known scheme for independent tampering was tailored to threshold access structures.
Category / Keywords: foundations / Secret sharing , Non-malleability, Leakage resilience Original Publication (with major differences): IACR-TCC-2019 Date: received 30 May 2019, last revised 24 Sep 2019 Contact author: antonio faonio at imdea org,brian 1615294@studenti uniroma1 it,venturi@di uniroma1 it Available format(s): PDF | BibTeX Citation Note: Full version. Version: 20190924:102802 (All versions of this report) Short URL: ia.cr/2019/602