An Efficient Adaptive-Deniable-Concurrent Non-malleable Commitment Scheme

Seiko ARITA  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E94-A   No.1   pp.367-382
Publication Date: 2011/01/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.E94.A.367
Print ISSN: 0916-8508
Type of Manuscript: PAPER
Category: Cryptography and Information Security
commitment schemes,  adaptivity,  deniability,  concurrency,  non-malleability,  

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It is known that composable secure commitments, that is, concurrent non-malleable commitments exist in the plain model, based only on standard assumptions such as the existence of claw-free permutations or even one-way functions. Since being based on the plain model, the deniability of them is trivially satisfied, and especially the latter scheme satisfies also adaptivity, hence it is adaptive-deniable-concurrent non-malleable. However, those schemes cannot be said to be practically efficient. We show a practically efficient (string) adaptive-deniable-concurrent commitment scheme is possible under a global setup model, called the Global CRS-KR model.