Specifically, we analyze our four-round protocols in the presence of malicious non-aborting adversaries (i.e. which do not abort prematurely) for which we obtain full simulation security and malicious aborting adversaries for which we obtain 1/p-security (which implies that the simulation fails with probability at most 1/p+\ngl) while guaranteeing full privacy against both parties. We realize the coin-tossing and oblivious transfer functionalities under these relaxations, and present protocols with different security guarantees. We also provide a tight characterization of when 1/p-security is achievable where full privacy is expected.
Category / Keywords: cryptographic protocols / Secure Computation, Coin-Tossing, Oblivious Transfer, Round Complexity Date: received 8 Aug 2015, last revised 17 Oct 2015 Contact author: carmit hazay at biu ac il Available format(s): PDF | BibTeX Citation Note: The revised version of October 17,2015 includes a new protocol for oblivious transfer that achieves the strongest security notion achievable in three rounds, namely, it provides full privacy against both parties and 1/p security against a malicious sender. It also includes a new result that proves optimality of this new construction by providing a matching lower bound. Version: 20151017:174823 (All versions of this report) Short URL: ia.cr/2015/797 Discussion forum: Show discussion | Start new discussion