New Constructions for Reusable, Non-erasure and Universally Composable Commitments
This paper proposes a novel construction of reusable and non-erasure commitment schemes in the common reference string model. We show that our implementation is secure in the universally composable paradigm assuming that the decisional Diffie-Hellman problem over a squared composite modulus of the form N =pq is hard. Our methodology relies on state-of-the-art double trap-door public-key encryption protocols so that a simulator in charge of a common reference string can extract messages of cipher-text rather than the equivocability of underlying cryptographic systems. As a result, our method differs from those presented in  and . The double trap-door mechanism is of great benefit to an ideal-world simulator since no modifications will be charged to unopened commitments in case that the participants who generated these commitments are corrupted, and thus enables us to implement efficient simulators in the ideal-world.
KeywordsNon-erasure reusability simulator universally composable commitment
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