New Communication-Efficient Oblivious Transfer Protocols Based on Pairings

摘要

We construct two simple families of two-message (n, l)-oblivious transfer protocols based on degree-t homomorphic cryptosystems with the communication of respectively 1 + [n/t] and 3 + [n/(t + 1)] ciphertexts. The construction of both families relies on efficient cryptocomputable conditional disclosure of secret protocols; the way this is done may be of independent interest. The currently most interesting case t = 2 can be based on the Boneh-Goh-Nissim cryptosystem. As an important application, we show how to reduce the communication of virtually any existing oblivious transfer protocols by proposing a new related communication-efficient generic transformation from computationally-private information retrieval protocols to oblivious transfer protocols.