Several Effective N K Casual Transmission Mode

Oblivious transfer has become a research hotspot since proposed. It could be used as basic primitives to construct cryptography protocols in theory, for instance, zero-knowledge proof, secret sharing, bit commitment, secure multiparty computation, and fair blind signature. On the other hand, oblivious transfer has more practical application, such as transferring the general primate information retrieval to symmetric private information retrieval, electronic contract signing, electronic voting, and so on.In this paper, some background knowledge about oblivious transfer was given first, followed by the research background, research meaning and a current research summary. Some concepts are explained, including secure multiparty computation, finite field, the Decisional Diffie-Hellman (DDH) assumption, the zero-knowledge proof, witness-indistinguishable proof knowledge and the random oracle model, whose advantages and disadvantages are also been given.Three k out of n oblivious transfer schemes, denoted by OTkn-I, OTkn-II, and OTkn-III, respectively, are given which is the major work of this paper. The proof of the correctness, the sender’s privacy and the receiver’s privacy are also given, respectively. And after that, a comparison with other k out of n oblivious transfer schemes is given which shows that our schemes require several messages to send by receivers while others O(k). It’s easy to say that our schemes are much more effective.At last, OTkn-III is used to translate a private information retrieval to a symmetric private information retrieval. And an analysis is given.