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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…

Quantum Physics · Physics 2016-09-12 Robert A Malaney

We show how continuous variable systems can allow the direct communication of messages with an acceptable degree of privacy. This is possible by combining a suitable phase-space encoding of the plain message with real-time checks of the…

Quantum Physics · Physics 2008-12-03 Stefano Pirandola , Samuel L. Braunstein , Stefano Mancini , Seth Lloyd

We study the role of quantum communication in attacks on quantum position verification. In this work, we construct the first known example of a QPV protocol that is provably secure against unentangled attackers restricted to classical…

Quantum Physics · Physics 2022-08-10 Rene Allerstorfer , Harry Buhrman , Florian Speelman , Philip Verduyn Lunel

In this work, we study position-based cryptography in the quantum setting. The aim is to use the geographical position of a party as its only credential. On the negative side, we show that if adversaries are allowed to share an arbitrarily…

We provide a security analysis for continuous variable quantum key distribution protocols based on the transmission of squeezed vacuum states measured via homodyne detection. We employ a version of the entropic uncertainty relation for…

Quantum position verification (QPV) is the art of verifying the geographical location of an untrusted party. Recently, it has been shown that the widely studied Bennett & Brassard 1984 (BB84) QPV protocol is insecure after the 3 dB loss…

Quantum Physics · Physics 2016-09-21 Charles Ci Wen Lim , Feihu Xu , George Siopsis , Eric Chitambar , Philip G. Evans , Bing Qi

Continuous variables (CV) offer a promising platform for the development of various applications, such as quantum communication, computing, and sensing, and CV graph states represent a family of powerful entangled resource states for all…

Quantum Physics · Physics 2025-02-11 Éloi Descamps , Damian Markham

Quantum digital signatures (QDSs), which utilize correlated bit strings among sender and recipients, guarantee the authenticity, integrity, and nonrepudiation of classical messages based on quantum laws. Continuous-variable (CV) quantum…

Quantum Physics · Physics 2024-11-25 Yi-Fan Zhang , Wen-Bo Liu , Bing-Hong Li , Hua-Lei Yin , Zeng-Bing Chen

We propose efficient-phase-encoding protocols for continuous-variable quantum key distribution using coherent states and postselection. By these phase encodings, the probability of basis mismatch is reduced and total efficiency is…

Quantum Physics · Physics 2008-09-29 Ryo Namiki , Takuya Hirano

Local unitary stabilizer subgroups constitute powerful invariants for distinguishing various types of multipartite entanglement. In this paper, we show how stabilizers can be used as a basis for entanglement verification protocols on…

Quantum Physics · Physics 2013-06-20 David W. Lyons , Scott N. Walck

Based on the instantaneous nonlocal quantum computation (INQC), Buhrman et al. proposed an excellent attack strategy to quantum position verification (QPV) protocols in 2011, and showed that, if the colluding adversaries are allowed to…

Quantum Physics · Physics 2013-05-21 Fei Gao , Bin Liu , Qiao-Yan Wen

The safety of a quantum key distribution system relies on the fact that any eavesdropping attempt on the quantum channel creates errors in the transmission. For a given error rate, the amount of information that may have leaked to the…

Quantum Physics · Physics 2009-10-28 B. Huttner , N. Imoto , N. Gisin , T. Mor

We consider continuous-variable quantum key distribution with discrete-alphabet encodings. In particular, we study protocols where information is encoded in the phase of displaced coherent (or thermal) states, even though the results can be…

Quantum Physics · Physics 2021-01-18 Panagiotis Papanastasiou , Stefano Pirandola

We propose a proof of the security of EPR-based quantum key distribution against enemies with unlimited computational power. The proof holds for a protocol using interactive error-reconciliation scheme. We assume in this paper that the…

Quantum Physics · Physics 2007-05-23 Hitoshi Inamori

In this letter, first, we investigate the security of a continuous-variable quantum cryptographic scheme with a postselection process against individual beam splitting attack. It is shown that the scheme can be secure in the presence of the…

Quantum Physics · Physics 2009-11-10 Ryo Namiki , Takuya Hirano

A continuous variable measurement device independent multi-party quantum communication protocol is investigated in this paper. Utilizing distributed continuous variable Greenberger-Horne-Zeilinger state, this protocol can implement both…

Quantum Physics · Physics 2016-03-02 Yadong Wu , Jian Zhou , Xinbao Gong , Ying Guo , Zhi-Ming Zhang , Guangqiang He

Continuous variable quantum cryptography has developed rapidly in recent decades, but how to verify identity in the continuous variable quantum system is still an urgent issue to be solved. To solve this problem, we propose a continuous…

Quantum Physics · Physics 2022-03-17 Xing-Qiang Zhao , Hai Wan , Lv-Zhou Li

Protocols for quantum position verification (QPV) which combine classical and quantum information are insecure in the presence of loss. We study the exact loss-tolerance of the most popular protocol for QPV, which is based on BB84 states,…

Quantum Physics · Physics 2025-07-10 Llorenç Escolà-Farràs , Florian Speelman

Building scalable and secure quantum networks with many users has a high application potential but also holds many practical challenges. A significant stride in this pursuit involves extending quantum key distribution, an…

Recently, position-based quantum cryptography has been claimed to be unconditionally secure. In contrary, here we show that the existing proposals for position-based quantum cryptography are, in fact, insecure if entanglement is shared…

Quantum Physics · Physics 2011-01-28 Hoi Kwan Lau , Hoi Kwong Lo