Improved Non-committing Encryption Schemes Based on a General Complexity Assumption

Abstract. Non-committing encryption enables the construction of multiparty computation protocols secure against an adaptive adversary in the computational setting where private channels between players are not assumed. While any non-committing encryption scheme must be secure in the ordinary semantic sense, the converse is not necessarily true. We propose a construction of non-committing encryption that can be based on any public-key system which is secure in the ordinary sense and which has an extra property we call simulatability. This generalises an earlier scheme proposed by Beaver based on the Diffie-Hellman problem, and we propose another implementation based on RSA. In a more general setting, our construction can be based on any collection of trapdoor permutations with a certain simulatability property. This offers a considerable efficiency improvement over the first non-committing encryption scheme proposed by Canetti et al. Finally, at some loss of efficiency, our scheme can...

• Type: Conference
• Year: 2000
• Where: CRYPTO
• Authors: Ivan Damgård, Jesper Buus Nielsen
• Keywords: CRYPTO 2000, Cryptology, Non-committing Encryption, Non-committing Encryption Scheme, Trapdoor Permutations