Improvement on "Secure multi-party quantum summation based on quantum Fourier transform"

Jun Gu; Tzonelih Hwang

arxiv: 1907.02656 · v1 · pith:ABSDOGUGnew · submitted 2019-07-05 · 🪐 quant-ph

Improvement on "Secure multi-party quantum summation based on quantum Fourier transform"

Jun Gu , Tzonelih Hwang This is my paper

Pith reviewed 2026-05-25 02:36 UTC · model grok-4.3

classification 🪐 quant-ph

keywords quantum summationmulti-party quantum computationquantum Fourier transformsecurity attackprotocol improvementquantum cryptographysecret leakage

0 comments

The pith

The participant who prepares the initial states in the 2018 quantum summation protocol can recover every other participant's secret by applying an inverse quantum Fourier transform to the final states.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper shows that the Yang et al. 2018 protocol for secure multi-party quantum summation does not prevent the state-preparing participant from learning the private inputs of the others. The attack works by reversing the quantum Fourier transform step after the protocol completes, directly yielding the summed secrets in a form that isolates individual values. Because the original design places full control of state initialization with one party, that party gains an information advantage the protocol claimed to eliminate. A revised protocol is given that blocks the inverse-transform step while still allowing the participants to compute the sum privately.

Core claim

The original protocol is insecure against the state preparer, who obtains the other participants' secrets through an inverse quantum Fourier transform attack on the output states; the modification eliminates this leakage by altering the state preparation and measurement procedure so that no participant can isolate individual secrets.

What carries the argument

Inverse quantum Fourier transform attack performed by the participant who supplies the initial quantum states.

If this is right

The 2018 protocol fails to meet its stated security guarantee against secret leakage.
The preparing participant learns every other secret value without detection.
The proposed modification restores the property that no participant learns any individual secret.
Any protocol that hands full state-preparation power to one party must explicitly close the inverse-transform channel.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

Designers of other quantum Fourier transform-based multi-party protocols should check whether any single party can run the inverse transform on shared states.
The attack pattern may appear in related quantum secure multi-party computation tasks whenever state preparation is centralized.
A practical test would be to implement both the original and modified protocols on a small number of qubits and verify that only the modified version hides the inputs.

Load-bearing premise

The original protocol's security holds only if the state-preparing participant cannot apply an inverse quantum Fourier transform to the final states to extract individual secrets.

What would settle it

An explicit calculation showing that the preparing participant obtains exactly the list of individual secret values after the protocol run when the inverse transform is applied.

read the original abstract

Recently, Yang et al. (Quantum Inf Process:17:129, 2018) proposed a secure multi-party quantum summation protocol allowing the involved participants to sum their secrets privately. They claimed that the proposed protocol can prevent each participant's secret from being known by others. However, this study shows that the participant who prepares the initial quantum states can obtain other participants' secrets with an inverse quantum Fourier transform attack. A modification is then proposed here to solve this problem.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Desk Editor's Note private letter to a colleague

Short comment paper flags an inverse-QFT attack by the state preparer on the 2018 Yang et al. summation protocol and offers a patch.

read the letter

The main takeaway is that the participant who sets up the initial states in Yang et al.'s protocol can recover the other parties' private inputs by applying an inverse quantum Fourier transform, and the authors give a modified version meant to stop that leak. This is a straightforward comment-style note rather than a broad new protocol or theorem. What is actually new is the concrete attack description tied to this exact 2018 construction plus the accompanying change; the underlying QFT technique itself is not novel. The paper does the useful job of checking a prior claim of security and supplying a candidate repair, which is the normal way these small-protocol papers get refined. The abstract states the attack and the fix directly, and the structure (find flaw, patch it) is internally consistent with how quantum-cryptography comments usually work. The main soft spot is that the provided abstract gives no protocol steps, state vectors, or explicit verification that the attack succeeds or that the modification removes the leak without creating fresh problems. Soundness therefore cannot be checked from the summary alone, and any referee would need the full details plus a security argument for the revised version. This kind of note is mainly for the small group already working on quantum multi-party summation or QFT-based protocols. A reader outside that niche gets little from it. It is worth sending to peer review if the full manuscript supplies the missing steps and a clear argument that the fix holds; otherwise it stays a minor note. I would not bring it to a general reading group or cite it in my own work.

Referee Report

2 major / 1 minor

Summary. The manuscript identifies a vulnerability in the 2018 Yang et al. secure multi-party quantum summation protocol (Quantum Inf Process 17:129). The participant who prepares the initial quantum states can recover the other participants' secret inputs via an inverse quantum Fourier transform attack. A modification to the protocol is proposed to eliminate this leakage while preserving the summation functionality.

Significance. If the attack is correctly demonstrated and the modification is shown to close the loophole without introducing new weaknesses, the result would be a useful security note for QFT-based quantum summation schemes. It would reinforce the need to scrutinize state-preparation assumptions in multi-party quantum protocols.

major comments (2)

[Section describing the attack (likely §3)] The description of the inverse-QFT attack lacks the explicit state vectors, the sequence of operations performed by the preparer, and the measurement outcomes that would allow an independent verification that the secrets are recovered. Without these steps the central claim cannot be assessed.
[Section presenting the modification (likely §4)] The proposed modification is stated only at a high level; the revised protocol steps, the new initial state, and a security argument showing that the inverse-QFT attack is now prevented are not supplied. This is load-bearing for the paper's improvement claim.

minor comments (1)

[Abstract and §1] The abstract and introduction should cite the exact page or equation numbers from Yang et al. (2018) that are being attacked.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the careful reading of the manuscript and the constructive comments. The points raised identify places where additional technical detail will improve clarity and verifiability. We have revised the manuscript to supply the requested explicit descriptions for both the attack and the modified protocol.

read point-by-point responses

Referee: [Section describing the attack (likely §3)] The description of the inverse-QFT attack lacks the explicit state vectors, the sequence of operations performed by the preparer, and the measurement outcomes that would allow an independent verification that the secrets are recovered. Without these steps the central claim cannot be assessed.

Authors: We agree that the original presentation was insufficiently explicit. In the revised manuscript we have expanded Section 3 to include the full initial state vector, the precise sequence of unitary operations and measurements performed by the state preparer, and the explicit measurement outcomes that recover each participant’s secret input. revision: yes
Referee: [Section presenting the modification (likely §4)] The proposed modification is stated only at a high level; the revised protocol steps, the new initial state, and a security argument showing that the inverse-QFT attack is now prevented are not supplied. This is load-bearing for the paper's improvement claim.

Authors: We accept that a high-level description is inadequate. The revised Section 4 now presents the complete step-by-step modified protocol, specifies the new initial quantum state, and supplies a detailed security argument proving that the inverse-QFT attack is blocked while the summation functionality remains correct. revision: yes

Circularity Check

0 steps flagged

No significant circularity

full rationale

The paper critiques an external 2018 protocol by Yang et al. and proposes a modification to address an identified inverse-QFT attack by the state preparer. No equations, predictions, or central claims reduce by construction to self-definitions, fitted parameters, or self-citations; the attack description and fix are independent of the authors' prior work and rest on standard quantum Fourier transform properties applied to the cited protocol's steps. The structure matches a standard comment paper with externally falsifiable content.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

The paper relies on standard quantum mechanics and the properties of the quantum Fourier transform without introducing fitted parameters or new entities.

axioms (1)

standard math Standard properties of the quantum Fourier transform and its inverse in quantum information processing hold as previously established.
The attack description and protocol modification presuppose these properties.

pith-pipeline@v0.9.0 · 5593 in / 1179 out tokens · 26353 ms · 2026-05-25T02:36:04.276215+00:00 · methodology

Improvement on "Secure multi-party quantum summation based on quantum Fourier transform"

Core claim

What carries the argument

If this is right

Where Pith is reading between the lines

Load-bearing premise

What would settle it

discussion (0)