Improved Non-committing Encryption with Applications to Adaptively Secure Protocols

We present a new construction of non-committing encryption schemes. Unlike the previous constructions of Canetti et al. (STOC ’96) and of Damg˚ard and Nielsen (Crypto ’00), our construction achieves all of the following properties: – Optimal round complexity. Our encryption scheme is a 2-round protocol, matching the round complexity of Canetti et al. and improving upon that in Damg˚ard and Nielsen. – Weaker assumptions. Our construction is based on trapdoor simulatable cryptosystems, a new primitive that we introduce as a relaxation of those used in previous works. We also show how to realize this primitive based on hardness of factoring. – Improved efficiency. The amortized complexity of encrypting a single bit is O(1) public key operations on a constant-sized plaintext in the underlying cryptosystem. As a result, we obtain the first non-committing public-key encryption schemes under hardness of factoring and worst-case lattice assumptions; previously, such schemes were ...

• Type: Conference
• Year: 2009
• Where: ASIACRYPT
• Authors: Seung Geol Choi, Dana Dachman-Soled, Tal Malkin, Hoeteck Wee
• Keywords: ASIACRYPT 2009, Cryptology, Encryption Schemes, Multi-party Computation, Secure Multi-party Computation