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Walter O. Krawec - One of the best experts on this subject based on the ideXlab platform.
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Key Rate bound of a semi quantum protocol using an entropic uncertainty relation
International Symposium on Information Theory, 2018Co-Authors: Walter O. KrawecAbstract:In this paper we present a new proof technique for semi-quantum Key distribution (SQKD) protocols which makes use of a quantum entropic uncertainty relation to bound an adversary's information. We develop several new techniques for analyzing SQKD protocols; furthermore, our new proof may hold application in the security analysis of other semi-quantum protocols or protocols relying on two-way quantum communication.
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ISIT - Key-Rate Bound of a Semi-Quantum Protocol Using an Entropic Uncertainty Relation
2018 IEEE International Symposium on Information Theory (ISIT), 2018Co-Authors: Walter O. KrawecAbstract:In this paper we present a new proof technique for semi-quantum Key distribution (SQKD) protocols which makes use of a quantum entropic uncertainty relation to bound an adversary's information. We develop several new techniques for analyzing SQKD protocols; furthermore, our new proof may hold application in the security analysis of other semi-quantum protocols or protocols relying on two-way quantum communication.
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Key-Rate Bound of a Semi-Quantum Protocol Using an Entropic Uncertainty Relation
arXiv: Quantum Physics, 2018Co-Authors: Walter O. KrawecAbstract:In this paper we present a new proof technique for semi-quantum Key distribution protocols which makes use of a quantum entropic uncertainty relation to bound an adversary's information. Our new technique provides a more optimistic Key-Rate bound than previous work relying only on noise statistics (as opposed to using additional mismatched measurements which increase the noise tolerance of this protocol, but at the cost of requiring four times the amount of measurement data). Our new technique may hold application in the proof of security of other semi-quantum protocols or protocols relying on two-way quantum communication.
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ISIT - Asymptotic analysis of a three state quantum cryptographic protocol
2016 IEEE International Symposium on Information Theory (ISIT), 2016Co-Authors: Walter O. KrawecAbstract:In this paper we consider a three-state variant of the BB84 quantum Key distribution (QKD) protocol. We derive a new lower-bound on the Key Rate of this protocol in the asymptotic scenario and use mismatched measurement outcomes to improve the channel estimation. Our new Key Rate bound remains positive up to an error Rate of 11%, exactly that achieved by the four-state BB84 protocol.
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Asymptotic Analysis of a Three State Quantum Cryptographic Protocol
arXiv: Quantum Physics, 2016Co-Authors: Walter O. KrawecAbstract:In this paper we consider a three-state variant of the BB84 quantum Key distribution (QKD) protocol. We derive a new lower-bound on the Key Rate of this protocol in the asymptotic scenario and use mismatched measurement outcomes to improve the channel estimation. Our new Key Rate bound remains positive up to an error Rate of $11\%$, exactly that achieved by the four-state BB84 protocol.
Norbert Lutkenhaus - One of the best experts on this subject based on the ideXlab platform.
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Numerical Calculations of Finite Key Rate for General Quantum Key Distribution Protocols
arXiv: Quantum Physics, 2020Co-Authors: Ian George, Jie Lin, Norbert LutkenhausAbstract:Finite Key analysis of quantum Key distribution (QKD) is an important tool for any QKD implementation. While much work has been done on the framework of finite Key analysis, the application to individual protocols often relies on the the specific protocol being simple or highly symmetric as well as represented in small finite-dimensional Hilbert spaces. In this work, we extend our pre-existing reliable, efficient, tight, and generic numerical method for calculating the asymptotic Key Rate of device-dependent QKD protocols in finite-dimensional Hilbert spaces to the finite Key regime using the security analysis framework of Renner. We explain how this extension preserves the reliability, efficiency, and tightness of the asymptotic method. We then explore examples which illustRate both the generality of our method as well as the importance of parameter estimation and data processing within the framework.
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Upper bounds for the secure Key Rate of the decoy-state quantum Key distribution
Physical Review A, 2009Co-Authors: Marcos Curty, Tobias Moroder, Norbert LutkenhausAbstract:The use of decoy states in quantum Key distribution (QKD) has provided a method for substantially increasing the secret Key Rate and distance that can be covered by QKD protocols with practical signals. The security analysis of these schemes, however, leaves open the possibility that the development of better proof techniques, or better classical post-processing methods, might further improve their performance in realistic scenarios. In this paper, we derive upper bounds on the secure Key Rate for decoy state QKD. These bounds are based basically only on the classical correlations established by the legitimate users during the quantum communication phase of the protocol. The only assumption about the possible post-processing methods is that double click events are randomly assigned to single click events. Further we consider only secure Key Rates based on the uncalibRated device scenario which assigns imperfections such as detection inefficiency to the eavesdropper. Our analysis relies on two preconditions for secure two-way and one-way QKD: The legitimate users need to prove that there exists no separable state (in the case of two-way QKD), or that there exists no quantum state having a symmetric extension (one-way QKD), that is compatible with the available measurements results. Both criteria have been previously applied to evaluate single-photon implementations of QKD. Here we use them to investigate a realistic source of weak coherent pulses. The resulting upper bounds can be formulated as a convex optimization problem known as a semidefinite program which can be efficiently solved. For the standard four-state QKD protocol, they are quite close to known lower bounds, thus showing that there are clear limits to the further improvement of classical post-processing techniques in decoy state QKD.
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one way quantum Key distribution simple upper bound on the secret Key Rate
Physical Review A, 2006Co-Authors: Tobias Moroder, Marcos Curty, Norbert LutkenhausAbstract:We present a simple method to obtain an upper bound on the achievable secret Key Rate in quantum Key distribution (QKD) protocols that use only unidirectional classical communication during the public-discussion phase. This method is based on a necessary precondition for one-way secret Key distillation; the legitimate users need to prove that there exists no quantum state having a symmetric extension that is compatible with the available measurements results. The main advantage of the obtained upper bound is that it can be formulated as a semidefinite program, which can be efficiently solved. We illustRate our results by analyzing two well-known qubit-based QKD protocols: the four-state protocol and the six-state protocol.
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Upper bound on the secret Key Rate distillable from effective quantum correlations with imperfect detectors
Physical Review A, 2006Co-Authors: Tobias Moroder, Marcos Curty, Norbert LutkenhausAbstract:We provide a simple method to obtain an upper bound on the secret Key Rate that is particularly suited to analyze practical realizations of quantum Key distribution protocols with imperfect devices. We consider the so-called trusted device scenario where Eve cannot modify the actual detection devices employed by Alice and Bob. The upper bound obtained is based on the available measurements results, but it includes the effect of the noise and losses present in the detectors of the legitimate users.
Xiang-bin Wang - One of the best experts on this subject based on the ideXlab platform.
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higher Key Rate of measurement device independent quantum Key distribution through joint data processing
Physical Review A, 2021Co-Authors: Cong Jiang, Xiang-bin WangAbstract:We propose a method named as double-scanning method, to improve the Key Rate of measurement-device-independent quantum Key distribution (MDI-QKD) drastically. In the method, two parameters are scanned simultaneously to tightened estimate the counts of single-photon pairs and the phase-flip error Rate jointly. Numerical results show that the method in this work can improve the Key Rate by $50\%-250\%$ in a typical experimental set-up. Besides, we study the optimization of MDI-QKD protocol with all parameters including the source parameters and failure probability parameters, over symmetric channel or asymmetric channel. Numerical results show that compared with the optimized results with only the source parameters, the all-parameter-optimization method could improve the Key Rate by about $10\%$.
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sending or not sending twin field quantum Key distribution breaking the direct transmission Key Rate
Physical Review A, 2020Co-Authors: Cong Jiang, Xiang-bin WangAbstract:We present improved results of sending-or-not-sending twin-field quantum Key distribution by using error rejection through two-way classical communications. Our error rejection method, especially our method of actively odd-parity pairing (AOPP) can drastically improve the performance of sending-or-not-sending twin-field protocol in both secure distance and Key Rate. Taking a typical experimental parameter setting, our method here improves the secure distance by 70 km to more than 100 km in comparison with the prior art results. Comparative study also shows advantageous in Key Rates at regime of long distance and large misalignment error Rate for our method here. The numerical results show that our method here can significantly exceed the absolute limit of direct transmission Key Rate, and also have an advantageous Key Rates higher than various prior art results by 10 to 20 times.
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Sending-or-not-sending twin-field quantum Key distribution: Breaking the direct transmission Key Rate
Physical Review A, 2020Co-Authors: Cong Jiang, Xiang-bin WangAbstract:We present improved method of sending-or-not-sending twin-field quantum Key distribution (SNS TF-QKD) based on its structure and the application of error rejection. %And we present iteration formula for bit-flip error Rate of the survived bits after error rejection. Taking the finite Key effect into consideration with only $10^{11}$ total pulses, we show that the method here exceeds the absolute limit of repeater-less Key Rate with whatever detection efficiency. We also make comparative study of different protocols numerically. It shows that the method here presents advantageous results at long distance regime and large noise regime, asymptotically or non-asymptotically. Applying the de Finetti theorem, we present the iteration formula of phase-flip error Rate for survived bits from odd-parity events only. With this, the performance of SNS protocol can be further improved a lot.
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making the decoy state measurement device independent quantum Key distribution practically useful
Physical Review A, 2016Co-Authors: Yiheng Zhou, Zongwen Yu, Xiang-bin WangAbstract:The relatively low Key Rate seems to be the major barrier to its practical use for the decoy state measurement device independent quantum Key distribution (MDIQKD). We present a 4-intensity protocol for the decoy-state MDIQKD that hugely raises the Key Rate, especially in the case the total data size is not large. Also, calculation shows that our method makes it possible for secure private communication with {\em fresh} Keys geneRated from MDIQKD with a delay time of only a few seconds.
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Tightened estimation can improve the Key Rate of MDI-QKD by more than $100\%$
arXiv: Quantum Physics, 2013Co-Authors: Yiheng Zhou, Xiang-bin WangAbstract:We present formulas to tightly upper bound the phase-flip errors in decoy state method by using 4 intensities. Our result compressed the bound to about a quarter of known result for MDI-QKD. Based on this, we find that the Key Rate is improved by more than $100\%$ given weak coherent state sources (WCS), and even more than $200\%$ with the heralded single-photon sources (HSPS).
Ryutaroh Matsumoto - One of the best experts on this subject based on the ideXlab platform.
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Key Rate of the B92 quantum Key distribution protocol with finite qubits
2015 IEEE International Symposium on Information Theory (ISIT), 2015Co-Authors: Hiroaki Sasaki, Ryutaroh Matsumoto, Tomohiko UyematsuAbstract:The Key Rate of the B92 quantum Key distribution protocol had not been reported before this research when the number of qubits is finite. We compute it by using the security analysis framework proposed by Scarani and Renner in 2008.
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improved asymptotic Key Rate of the b92 protocol
International Symposium on Information Theory, 2013Co-Authors: Ryutaroh MatsumotoAbstract:We analyze the asymptotic Key Rate of the single photon B92 protocol by using Renner's security analysis given in 2005. The new analysis shows that the B92 protocol can securely geneRate Key at 6.5% depolarizing Rate, while the previous analyses cannot guarantee the secure Key generation at 4.2% depolarizing Rate.
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ISIT - Improved asymptotic Key Rate of the B92 protocol
2013 IEEE International Symposium on Information Theory, 2013Co-Authors: Ryutaroh MatsumotoAbstract:We analyze the asymptotic Key Rate of the single photon B92 protocol by using Renner's security analysis given in 2005. The new analysis shows that the B92 protocol can securely geneRate Key at 6.5% depolarizing Rate, while the previous analyses cannot guarantee the secure Key generation at 4.2% depolarizing Rate.
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Secure Key Rate of the BB84 Protocol using Finite Sample Bits
Journal of Physics A: Mathematical and Theoretical, 2010Co-Authors: Yousuke Sano, Ryutaroh Matsumoto, Tomohiko UyematsuAbstract:We improve the non-asymptotic Key Rate shown by Scarani and Renner by proposing several methods to construct tighter conservative confidence intervals of the phase error Rate than one shown by them. In addition, we show that the accuRate channel estimation method non-asymptotically increases the Key Rate over the amplitude damping channel as well as the asymptotic case in the BB84 protocol.
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Bit Transmission Probability Maximizing the Key Rate of the BB84 Protocol
arXiv: Quantum Physics, 2010Co-Authors: Sonny Lumbantoruan, Ryutaroh Matsumoto, Tomohiko UyematsuAbstract:In all papers on the BB84 protocol, the transmission probability of each bit value is usually set to be equal. In this paper, we show that by assigning different transmission probability to each transmitted qubit within a single polarization basis, we can generally improve the Key generation Rate of the BB84 protocol and achieve a higher Key Rate.
Tomohiko Uyematsu - One of the best experts on this subject based on the ideXlab platform.
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Key Rate of the B92 quantum Key distribution protocol with finite qubits
2015 IEEE International Symposium on Information Theory (ISIT), 2015Co-Authors: Hiroaki Sasaki, Ryutaroh Matsumoto, Tomohiko UyematsuAbstract:The Key Rate of the B92 quantum Key distribution protocol had not been reported before this research when the number of qubits is finite. We compute it by using the security analysis framework proposed by Scarani and Renner in 2008.
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Secure Key Rate of the BB84 Protocol using Finite Sample Bits
Journal of Physics A: Mathematical and Theoretical, 2010Co-Authors: Yousuke Sano, Ryutaroh Matsumoto, Tomohiko UyematsuAbstract:We improve the non-asymptotic Key Rate shown by Scarani and Renner by proposing several methods to construct tighter conservative confidence intervals of the phase error Rate than one shown by them. In addition, we show that the accuRate channel estimation method non-asymptotically increases the Key Rate over the amplitude damping channel as well as the asymptotic case in the BB84 protocol.
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Bit Transmission Probability Maximizing the Key Rate of the BB84 Protocol
arXiv: Quantum Physics, 2010Co-Authors: Sonny Lumbantoruan, Ryutaroh Matsumoto, Tomohiko UyematsuAbstract:In all papers on the BB84 protocol, the transmission probability of each bit value is usually set to be equal. In this paper, we show that by assigning different transmission probability to each transmitted qubit within a single polarization basis, we can generally improve the Key generation Rate of the BB84 protocol and achieve a higher Key Rate.
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ISIT - Secure Key Rate of the BB84 protocol using finite sample bits
2010 IEEE International Symposium on Information Theory, 2010Co-Authors: Yousuke Sano, Ryutaroh Matsumoto, Tomohiko UyematsuAbstract:We improve the non-asymptotic Key Rate shown by Scarani and Renner by proposing several methods to construct tighter conservative confidence interval of the phase error Rate than the one shown by them. In addition, we show that the accuRate channel estimation method non-asymptotically increases the Key Rate over the amplitude damping channel as well as the asymptotic case in the BB84 protocol.
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Tomography increases Key Rates of quantum-Key-distribution protocols
Physical Review A, 2008Co-Authors: Shun Watanabe, Ryutaroh Matsumoto, Tomohiko UyematsuAbstract:We construct a practically implementable classical processing for the Bennett-Brassard 1984 (BB84) protocol and the six-state protocol that fully utilizes the accuRate channel estimation method, which is also known as the quantum tomography. Our proposed processing yields at least as high a Key Rate as the standard processing by Shor and Preskill. We show two examples of quantum channels over which the Key Rate of our proposed processing is strictly higher than the standard processing. In the second example, the BB84 protocol with our proposed processing yields a positive Key Rate even though the so-called error Rate is higher than the 25% limit.
