Security verification for continuous variable quantum key distribution

Device-independence for two-party cryptography and position verification

Quantum communication has demonstrated its usefulness for quantum cryptography far beyond quantum key distribution. One domain is two-party cryptography, whose goal is to allow two parties who may not trust each other to solve joint tasks. Another interesting application is position-based cryptography whose goal is to use the geographical location of an entity as its only identifying credential. Unfortunately, security of these protocols is not possible against an all powerful adversary. However, if we impose some realistic physical constraints on the adversary, there exist protocols for which…

Experimental preparation and verification of quantum money

A quantum money scheme enables a trusted bank to provide untrusted users with verifiable quantum banknotes that cannot be forged. In this work, we report an experimental demonstration of the preparation and verification of unforgeable quantum banknotes. We employ a security analysis that takes experimental imperfections fully into account. We measure a total of $3.6\times 10^6$ states in one verification round, limiting the forging probability to $10^{-7}$ based on the security analysis. Our results demonstrate the feasibility of preparing and verifying quantum banknotes using currently availa…

量子位置验证的安全性通过全息原理限制了哈密顿量模拟

Security of quantum position-verification limits Hamiltonian simulation via holography

本文利用全息量子纠错码玩具模型，探讨量子位置验证与全息原理的联系，并证明位置验证安全性可导出哈密顿量模拟资源的新下界。

通过叠加实现的量子令牌混淆：一种使用多基验证与熵驱动演化的后量子安全框架

Quantum Token Obfuscation via Superposition: A Post-Quantum Security Framework Using Multi-Basis Verification and Entropy-Driven Evolution

针对量子计算对传统令牌混淆的威胁，本文提出一种利用量子叠加、多基验证与熵驱动演化的后量子安全框架，实验证实其在防止未授权重构方面具有极高安全性与零攻击成功率。

单次执行中任意容忍损耗的量子位置验证

Arbitrarily Loss-Tolerant Quantum Position Verification in a Single Execution

针对量子位置验证在单次执行中面临纠缠攻击和光子损耗的挑战，提出基于无信令关联的承诺修改方案，实现任意损耗容忍，安全性与底层协议一致，且对抗有界纠缠攻击者。

电路模型中基于魔法盲性的可组合验证

Composable Verification in the Circuit-Model via Magic-Blindness

本文引入一族针对Clifford+MSI电路的噪声鲁棒、可组合且高效的验证协议，通过魔法盲性概念实现与MBQC模型同等的安全性和鲁棒性，并降低量子通信成本。

为何裁剪与选择量子态验证无法同时高效且安全

Why cut-and-choose quantum state verification cannot be both efficient and secure

本研究证明裁剪与选择量子态验证无法同时实现高效和安全，揭示了其在独立安全性和可组合安全性下的根本限制。

Experimental verification of a fully inseparable tripartite continuous-variable state

A continuous-variable tripartite entangled state is experimentally generated by combining three independent squeezed vacuum states and the variances of its relative positions and total momentum are measured. We show that the measured values violate the separability criteria based on the sum of these quantities and prove the full inseparability of the generated state.

Efficient verification of entangled continuous-variable quantum states with local measurements

Continuous-variable quantum states are of particular importance in various quantum information processing tasks including quantum communication and quantum sensing. However, a bottleneck has emerged with the fast increasing in size of the quantum systems which severely hinders their efficient characterization. In this work, we establish a systematic framework for verifying entangled continuous-variable quantum states by employing local measurements only. Our protocol is able to achieve the unconditionally high verification efficiency which is quadratically better than quantum tomography as wel…

Fundamental Security Issues in Continuous Variable Quantum Key Distribution

Several fundamental issues in establishing security in continuous variable quantum key distribution are discussed, in particular on reverse reconciliation and security under heterodyne attack. It appears difficult to derive quantum advantage in a concrete realistic protocol due to source and loss uncertainties, apart from the problem of bounding Eve's information after reconciliation. The necessity of proving robust security for QKD protocols is indicated.

Quantum Locker Using a Novel Verification Algorithm and Its Experimental Realization in IBM Quantum Computer

It is well known that Grover's algorithm asymptotically transforms an equal superposition state into an eigenstate (of a given basis). Here, we demonstrate a verification algorithm based on weak measurement which can achieve the same purpose even if the qubit is not in an equal superposition state. The proposed algorithm highlights the distinguishability between any arbitrary single qubit superposition state and an eigenstate. We apply this algorithm to propose the scheme of a Quantum Locker, a protocol in which any legitimate party can verify his/her authenticity by using a newly developed qu…

Fully general device-independence for two-party cryptography and position verification

Device-independent quantum cryptography allows security even if the devices used to execute the protocol are untrusted - whether this is due to unknown imperfections in the implementation, or because the adversary himself constructed them to subvert the security of the protocol. While device-independence has seen much attention in the domain of quantum key distribution, relatively little is known for general protocols. Here we introduce a new model for device-independence for two-party protocols and position verification in the noisy-storage model. For the first time, we show that such protoco…

Simple security proofs for continuous-variable quantum key distribution with intensity fluctuating sources

Quantum Key Distribution (QKD) in principle offers unconditional security based on the laws of physics. Continuous variable (CV) quantum key distribution has the potential for high-key-rate and low-cost implementations using standard telecom components. Despite tremendous theoretical and experimental progress in continuous-variable quantum key distribution, the security has not been rigorously established for most current continuous-variable quantum key distribution systems that have imperfections. Among the imperfections, intensity fluctuation is a significant principal problem affecting secu…

Towards practical security of continuous-variable quantum key distribution

Rigorous mathematical proofs of the security of continuous-variable quantum key distribution (CV QKD) have been obtained recently. Unfortunately, these security proofs rely on assumptions that are hardly met in experimental practice. Here I investigate these issues in detail, and discuss experimentally-friendly workarounds to assess the security of CV QKD. The aim of this paper is to show that there are hidden and unsolved issues and to indicate possible partial solutions. To provide a complete and rigorous mathematical security proof is out of the scope of this contribution.

经典验证者基于非局域博弈的位置验证

Classical Verifier Position Verification from Non-Local Games

本文提出一个通用编译器，将非局域博弈映射为经典验证者位置验证协议，实现完全经典通信并仅需共享纠缠与局域测量，以CHSH博弈实例化并证明有限尺寸安全性。

使现有量子位置验证协议对任意传输损耗具有安全性

Making Existing Quantum Position Verification Protocols Secure Against Arbitrary Transmission Loss

本文提出了一种改进的量子位置验证协议，通过引入光子存在检测和时间延迟等措施，增强了协议对传输损耗的抗性，从而在实际应用中提供了更强的安全保障。

Symbolic Abstractions for Quantum Protocol Verification

Quantum protocols such as the BB84 Quantum Key Distribution protocol exchange qubits to achieve information-theoretic security guarantees. Many variants thereof were proposed, some of them being already deployed. Existing security proofs in that field are mostly tedious, error-prone pen-and-paper proofs of the core protocol only that rarely account for other crucial components such as authentication. This calls for formal and automated verification techniques that exhaustively explore all possible intruder behaviors and that scale well. The symbolic approach offers rigorous, mathematical frame…

针对广义对手的高效多基量子位置验证安全性

Efficient Multi-basis Quantum Position Verification Secure against Generalized Adversaries

研究针对广义对手的量子位置验证安全性，通过引入稳健协议、完善安全分析技术及解决隐含假设做出三项关键贡献，还举例展示了QPV在量子密钥分发中认证经典通信的应用。

模格点安全（第一部分）：Weber猜想的无条件验证 $k \le 12$

Module Lattice Security (Part I): Unconditional Verification of Weber's Conjecture for $k \le 12$

本文通过结合Fukuda-Komatsu计算筛法、环上整数环的归纳结构和Herbrand定理，首次无条件证明了Weber猜想在 $k \le 12$ 时的成立，解决了格基密码学中主理想问题、模环自由性和环LWE与模LWE最坏到平均情况的紧性问题。

Duality of extremal quantum states in verification and data hiding

Quantum state verification (QSV) and quantum data hiding (QDH) have so far been studied separately. QSV decides whether a given quantum state is close to the ideal one, with significantly lower sample complexity compared with direct application of quantum tomography. On the other hand, QDH is a cryptographic protocol that encodes secret classical information in multipartite quantum states, providing stronger security guarantees than conventional classical secret-sharing schemes. Here, we consider two fundamental quantities of a pure quantum state, determining the sample complexity needed for Q…

Toward automatic verification of quantum cryptographic protocols

Several quantum process algebras have been proposed and successfully applied in verification of quantum cryptographic protocols. All of the bisimulations proposed so far for quantum processes in these process algebras are state-based, implying that they only compare individual quantum states, but not a combination of them. This paper remedies this problem by introducing a novel notion of distribution-based bisimulation for quantum processes. We further propose an approximate version of this bisimulation that enables us to prove more sophisticated security properties of quantum protocols which …

使用相对论零知识证明系统的量子安全身份验证

Quantum-Safe Identity Verification using Relativistic Zero-Knowledge Proof Systems

本文研究基于相对论零知识证明的量子安全身份验证，通过将距离约束从60米放宽至30米、提升实验稳定性与可扩展性、提出抗纠缠恶意证明者的修改协议并扩展至三证明者配置，解决了现有方案的安全与工程问题。

Broken Quantum: 对开源量子计算模拟器生态系统中安全漏洞的系统形式验证研究

Broken Quantum: A Systematic Formal Verification Study of Security Vulnerabilities Across the Open-Source Quantum Computing Simulator Ecosystem

本文通过COBALT QAI工具对45个开源量子模拟框架进行形式化安全审计，发现547个安全漏洞，包括新型量子特定攻击向量QASM注入，并验证所有13种漏洞模式。

Generalized security analysis framework for continuous-variable quantum key distribution

Security of practical continuous-variable quantum key distribution is addressed and a security analysis framework, which does not rely on phase-space symmetries of signal states and correlations, is developed. In a general purification-based approach, following optimality of Gaussian collective attacks, it is suggested to find an equivalent generally mixed two-mode state shared between the trusted parties and then purifying it using Bloch-Messiah decomposition. This allows to assess security of the schemes with arbitrary parameters, which can be typically expected in experiments. It also allow…

Quantum Location Verification in Noisy Channels

Recently it has been shown how the use of quantum entanglement can lead to the creation of real-time communication channels whose viability can be made location dependent. Such functionality leads to new security paradigms that are not possible in classical communication networks. Key to these new security paradigms are quantum protocols that can unconditionally determine that a receiver is in fact at an a priori assigned location. A limiting factor of such quantum protocols will be the decoherence of states held in quantum memory. Here we investigate the performance of quantum location verifi…

增强的基于瑞尼熵的后量子密钥协议及其可证明安全性和信息论保证

Enhanced Rényi Entropy-Based Post-Quantum Key Agreement with Provable Security and Information-Theoretic Guarantees

本文提出了一种基于瑞尼熵的后量子密钥协议，通过熵保持操作和秘密共享验证实现可证明安全性和信息论保证，提供 $2^{128}$ 的量子安全保证。