Cheating in quantum Rabin oblivious transfer using delayed measurements

TL;DR

This paper demonstrates a vulnerability in quantum Rabin oblivious transfer protocols where delayed measurements enable cheating, and proposes modifications to reduce cheating success rates.

Contribution

It reveals a new attack method using delayed measurements in quantum Rabin oblivious transfer and suggests protocol modifications to mitigate this vulnerability.

Findings

Delayed measurement attack enables perfect cheating

Existing protocols are vulnerable to this attack

Proposed modifications reduce cheating probability

Abstract

Oblivious transfer has been the interest of study as it can be used as a building block for multiparty computation. There are many forms of oblivious transfer; we explore a variant known as Rabin oblivious transfer. Here the sender Alice has one bit, and the receiver Bob obtains this bit with a certain probability. The sender does not know whether the receiver obtained the bit or not. For a previously suggested protocol, we show a possible attack using a delayed measurement. This allows a cheating party to pass tests carried out by the other party, while gaining more information than if they would have been honest. We show how this attack allows perfect cheating, unless the protocol is modified, and suggest changes which lower the cheating probability for the examined cheating strategies.