1-out-of-2 Oblivious transfer using flawed Bit-string quantum protocol

TL;DR

This paper presents a reduction method for a quantum-based all-or-nothing oblivious transfer protocol, maintaining its security while adapting it to a 1-out-of-2 OT setting, addressing a gap in quantum cryptography.

Contribution

It introduces a novel reduction technique that transforms a quantum all-or-nothing OT protocol into a 1-out-of-2 OT protocol without compromising security.

Findings

The reduction preserves the security of the original protocol.

It demonstrates the feasibility of adapting quantum OT protocols to different variants.

The approach bridges a gap between all-or-nothing and 1-out-of-2 OT protocols in quantum cryptography.

Abstract

Oblivious transfer (OT) is an important tool in cryptography. It serves as a subroutine to other complex procedures of both theoretical and practical significance. Common attribute of OT protocols is that one party (Alice) has to send a message to another party (Bob) and has to stay oblivious on whether Bob did receive the message. Specific (OT) protocols vary by exact definition of the task - in the all-or-nothing protocol Alice sends a single bit-string message, which Bob is able to read only with 50% probability, whereas in 1-out-of-2 OT protocol Bob reads one out of two messages sent by Alice. These two flavours of protocol are known to be equivalent. Recently a computationally secure all-or-nothing OT protocol based on quantum states was developed in [A. Souto et. al., PRA 91, 042306], which however cannot be reduced to 1-out-of-2 OT protocol by standard means. Here we present an elaborated reduction of this protocol which retains the security of the original.