Oblivious Transfer Based on NTRUEncrypt

Abstract

Oblivious transfer (OT) is the most fundamental process in cryptosystems and serves as the basic building block for implementing protocols, such as the secure multi-party computation and the fair electronic contract. However, since most implementations of the Internet of Things are time-sensitive, existing works that are based on traditional public cryptosystems are not efficient or secure under quantum machine attacks. In this paper, we argued that the fastest known 1-out-of-n oblivious transfer ( ${\mathrm {OT}}_{n}^{1}$ ) protocol, which was proposed by Chou, cannot achieve semantic security and is time-consuming due to exponent arithmetic of large parameters. Utilizing NTRUEncrypt and OT extension, we devised a one-round post-quantum secure ${\mathrm {OT}}_{n}^{1}$ protocol that is also proved to be active and adaptively secure under the universal composability framework. Compared with Chou’s protocol, the computational overheads of our scheme are approximately 6 and 1.7 times smaller on the sender and receiver sides, in line with the standard security level.