Non-interactive CCA-Secure threshold cryptosystems with adaptive security: new framework and constructions
Proceedings of the 9th international conference on Theory of Cryptography, Springer-Verlag, Berlin, Heidelberg (2012), pp. 75-93
Benoit Libert, Moti Yung
This paper describes a general construction of adaptively secure robust non-interactive threshold cryptosystems with chosen-ciphertext security. We dene the notion of all-but-one perfectly sound threshold hash proof systems that can be seen as (threshold) hash proof systems with publicly verifiable and simulation-sound proofs. We show that this notion generically implies threshold cryptosystems combining the aforementioned properties. Then, we provide ecient instantiations under well-studied assumptions in bilinear groups (e.g., in such groups of prime order). These instantiations have a tighter security proof and are indeed compatible with distributed key generation protocols.