Quadratically Secure Oblivious Transfer from Strong one-Way Functions.

Keisuke Tanaka, Akihiro Yamada, Kenji Yasunaga

圭介 田中, Keisuke Tanaka, 章央 山田 +3 more

Ping Wang, Rui Zhang, Guohao Jiang +1 more

Abstract Oblivious transfer (OT) is one of the cornerstones of secure multiparty computation. It is clear that unconditionally secure OT is impossible. Any protocol for OT requires computational assumptions, such as number‐theoretic cryptographic assumptions or the assumptions of existence of one‐way functions. On the other hand, it is broadly believed that one‐way functions alone do not promise secure OT. However, in this paper, a novel computationally secure quantum oblivious transfer (QOT) protocol is proposed with the help of quantum channels under the minimum assumption requirements: the existence of one‐way functions.

Ping Wang, Yiting Su, Zhiwei Sun

Oblivious transfer (OT) is one of the keystones of secure multi-party computation. It is generally believed that unconditionally secure OT is impossible. In this article, we propose a practical and secure quantum all-or-nothing oblivious transfer protocol based on the quantum one-way function. The protocol is built upon a quantum public-key encryption construction, and its security relies on the no-cloning theorem and no-communication theorem. Practical security is reflected in limitations on non-demolition measurements.

Moni Naor, Benny Pinkas B

Yehuda Lindell, Hila Zarosim

Oblivious transfer is one of the most basic and important building blocks in cryptography. As such, understanding its cost is of prime importance. Beaver (STOC 1996) showed that it is possible to obtain poly(n) oblivious transfers given only n actual oblivious transfer calls and using one-way functions, where n is the security parameter. In addition, he showed that it is impossible to extend oblivious transfer information theoretically. The notion of extending oblivious transfer is important theoretically (to understand the complexity of computing this primitive) and practically (since oblivious transfers can be expensive and thus extending them using only one-way functions is very attractive). Despite its importance, very little is known about the feasibility of extending oblivious transfer, beyond the fact that it is impossible information theoretically. Specifically, it is not known whether or not one-way functions are actually necessary for extending oblivious transfer, whether or not it is possible to extend oblivious transfers with adaptive security, and whether or not it is possible to extend oblivious transfers when starting with just a few. In this paper, we address these questions and provide almost complete answers to all of them. We show that the existence of any oblivious transfer extension protocol with security for static semihonest adversaries implies one-way functions, that an oblivious transfer extension protocol with adaptive security implies oblivious transfer with static security, and that the existence of an oblivious transfer extension protocol from only O(log n) oblivious transfers implies oblivious transfer itself.