# Improvements on "Secure multi-party quantum summation based on quantum Fourier transform"

## TL;DR

This paper identifies vulnerabilities in a quantum multi-party summation protocol based on quantum Fourier transform and proposes improvements that enhance security and simplify the protocol by removing the need for quantum Fourier transform and participant encoding.

## Contribution

The paper uncovers specific attacks on an existing quantum summation protocol and introduces countermeasures, resulting in a more secure and simplified protocol.

## Key findings

- Identified two attacks that compromise the original protocol.
- Proposed countermeasures successfully prevent the attacks.
- The improved protocol does not require quantum Fourier transform or participant encoding.

## Abstract

Recently, a quantum multi-party summation protocol based on the quantum Fourier transform has been proposed [Quantum Inf Process 17: 129, 2018]. The protocol claims to be secure against both outside and participant attacks. However, a closer look reveals that the player in charge of generating the required multi-partite entangled states can launch two kinds of attacks to learn about other parties' private integer strings without being caught. In this paper, we present these attacks, and propose countermeasures to make the protocol secure again. The improved protocol not only can resist these attacks but also remove the need for the quantum Fourier transform and encoding quantum operations by participants.