Related papers: Reply To "Comment on 'Quantum String Seal Is Insec…
We analyze a cryptographic protocol for generating a distributed secret key from correlations that violate a Bell inequality by a sufficient amount, and prove its security against eavesdroppers, constrained only by the assumption that any…
The relationship between the quantum bit commitment (QBC) and quantum seal (QS) is studied. It is elaborated that QBC and QS are not equivalent, but QS protocols satisfying a stronger unconditional security requirement can lead to an…
Recently proposed idea of "protective" measurement of a quantum state is critically examined, and generalized. Earlier criticisms of the idea are discussed and their relevance to the proposal assessed. Several constraints on measuring…
Recently, in Sci. Rep. \textbf{6} (2016) 28767, Li et al., have proposed a scheme for quantum key distribution using Bell states. This comment provides a proof that the proposed scheme of Li et al., is insecure as it involves leakage of…
The importance of quantum key distribution as a cryptographic method depends upon its purported strong security guarantee. The following gives reasons on why such strong security guarantee has not been validly established and why good QKD…
Quantum Key Distribution (QKD) has been attracting researchers that it would provide provable security to distribute secret keys since its birth in 1984. Since 2005, the trace distance between an ideal quantum state and an actually…
Quantum communication offers unique features that have no classical analog, in particular, it enables provably secure quantum key distribution (QKD). Despite the benefits of quantum communication are well understood within the scientific…
Recently, Zou et al. [Phys. Rev. A 82, 042325 (2010)] pointed out that two arbitrated quantum signature (AQS) schemes are not secure, because an arbitrator cannot arbitrate the dispute between two users when a receiver repudiates the…
In 2004, Ba An Nguyen [Phys. Lett. A 328, 6-10] has presented a Quantum Dialogue scheme for simultaneously communicating their messages. In this comment, we show that the quantum dialogue scheme is not secure against the…
In the paper [Zhang, Li and Guo, Phys. Rev. A 64, 024302 (2001)], a quantum key distribution protocol based on quantum encryption was proposed, in which the quantum key can be reused. However, it is shown that, if Eve employs a special…
Secure communication is considered with unreliable entanglement assistance, where the adversary may intercept the legitimate receiver's entanglement resource before communication takes place. The communication setting of unreliable…
We consider a simple string model to explain and partly demystify the phenomenon of quantum entanglement. The model in question has nothing to do with string theory: it uses macroscopic strings that can be acted upon by Alice and Bob in…
In contrast to classical public-key cryptosystems, where the security of encoded messages relies on on computational assumptions, Quantum Key Distribution (QKD) enables two distant parties to establish a shared secret key that, when…
Designing a quantum key agreement (QKA) protocol is always a challenging task, because both the security and the fairness properties have to be considered simultaneously. Recently, Zhu et al. (Quantum Inf Process 14(11): 4245-4254) pointed…
We address criticism of the Letter "Exposed-Key Weakness of $\alpha \eta$" in the Comment by Nair and Yuen. The Comment claims that the Letter does not show insecurity of $\alpha \eta$ because our approximation for the eavesdropper's…
Unconditionally secure non-relativistic bit commitment is known to be impossible in both the classical and the quantum world. However, when committing to a string of n bits at once, how far can we stretch the quantum limits? In this letter,…
Despite enormous progress both in theoretical and experimental quantum cryptography, the security of most current implementations of quantum key distribution is still not established rigorously. One of the main problems is that the security…
It is revealed that quantum repeating devices and quantum seals have a very close relationship, thus the theory in one field can be applied to the other. Consequently, it is shown that the fidelity bounds and optimality of quantum repeating…
In a series of recent papers, Hirota and Yuen claim to have identified a fundamental flaw in the theory underlying quantum cryptography, which would invalidate existing security proofs. In this short note, we sketch their argument and show…
Many papers proved the security of quantum key distribution (QKD) system, in the asymptotic framework. The degree of the security has not been discussed in the finite coding-length framework, sufficiently. However, to guarantee any…