Improved Non-committing Encryption with Applications to Adaptively Secure Protocols

摘要: We present a new construction of non-committing encryption schemes. Unlike the previous constructions Canetti et al. (STOC '96) and Damgard Nielsen (Crypto '00), our achieves all following properties: Optimal round complexity. Our scheme is 2-round protocol, matching complexity improving upon that in Nielsen. Weaker assumptions. based on trapdoor simulatable cryptosystems , primitive we introduce as relaxation those used works. also show how to realize this hardness factoring. Improved efficiency. The amortized encrypting single bit O (1) public key operations constant-sized plaintext underlying cryptosystem. As result, obtain first public-key schemes under factoring worst-case lattice assumptions; previously, such were only known CDH RSA Combined with existing work secure multi-party computation, protocols for computation against malicious adversary may adaptively corrupt an arbitrary number parties weaker assumptions than previously known. Specifically, both stand-alone setting UC common reference string.