Adaptive and Composable Oblivious Transfer Protocols

摘要

An adaptive k-out-of-n oblivious transfer protocol ((OT_(k×1))~n) allows a receiver to obtain (m_σ)_(i-1) before deciding on the i-th index σ_i. This paper studies adaptive k-out-of-n oblivious transfer protocols in the presence of static adversaries in the universal composition (UC) framework. We show that the proposed ((OT_(k×1))~n) protocol realizes the UC-security in the (F_(crs))~D-hybrid model under the joint assumptions that the underlying signature scheme is secure, the decisional Diffie-Hellman problem and the decisional composite residuosity problem in Z_(N~2) are hard as well as all knowledge proof protocols applied in this paper are computational zero-knowledge in the presence of static adversaries.