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

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 adaptivedeniable-concurrent non-malleable. However, those schemes cannot be said to be practically efficient. We show a practically efficient (string) adaptive-deniable-concurrent commitment schemes is possible under a global setup model, called a global CRS-KR model. keywords: commitment schemes, adaptivity, deniability, concurrency, non-malleability.