Uniquely among the sciences, quantum cryptography has driven both foundational research as well as practical real-life applications. We review the progress of quantum cryptography in the last decade, covering quantum key distribution and other applications. Quanta 2017; 6: 1–47.

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Quantum Cryptography: Key Distribution and Beyond

Uniquely among the sciences, quantum cryptography has driven both foundational research as well as practical real-life applications. We review the progress of quantum cryptography in the last decade, covering quantum key distribution and other applications.

Quantum cryptography: key distribution and beyond

We analyze the security of an inter-bank E-payment protocol based on quantum proxy blind signature, and find that there is a security leak in the quantum channels of this protocol, which gives a chance for an outside opponent to launch a special denial-of-service attack. Furthermore, we show that the dishonest merchant can succeed to change the purchase information of the customer in this protocol.

Cryptanalysis of an inter-bank E-payment protocol based on quantum proxy blind signature

A multi-proxy strong blind quantum signature scheme is proposed in this paper. An original signatory Alice delegates her signing authority to a group of proxy signatories by using a classical warrant. A blind factor is introduced by a sender U to blind a message, and the proxy signatories sign the message blindly via applying appropriate unitary operators. A receiver Bob verifies the generated signature with the help of an arbitrator Trent. The security of this scheme is based on a quantum key distribution protocol, a quantum one-time pad and other quantum properties. It is proved that our scheme has the properties of non-disavowal, non-counterfeit, multi-proxy, blindness, untraceability and can resist some common attacks.

Multi-proxy Strong Blind Quantum Signature Scheme

We analyze the security of a sessional blind signature protocol based on quantum cryptograph and show that there are two security leaks in this protocol. One is that the legal user Alice can change the signed message after she gets a valid blind signature from the signatory Bob, and the other is that an external opponent Eve also can forge a valid blind message by a special attack, which are not permitted for blind signature. Therefore, this protocol is not secure in the sense that it does not satisfy the non-forgeability of blind signatures. We also discuss the methods to prevent the attack strategies in the end.

Security of a sessional blind signature based on quantum cryptograph

Security and anonymity are essential to E-payment systems. However, with the increasing computing power, existing E-payment systems will gradually become insecure. In this paper, we propose an inter-bank E-payment system which is based on quantum proxy blind signature. Adopting the techniques of quantum key distribution, one-time pad and quantum proxy blind signature, our quantum E-payment system could protect user's anonymity as the traditional E-payment systems do, and also have unconditional security which the classical E-payment systems cannot provide. Furthermore, compared with the existing quantum E-payment systems, the proposed system could support inter-bank transactions.

An inter-bank E-payment protocol based on quantum proxy blind signature

Reconciliation is a crucial procedure for continuous-variable quantum key distribution (CV-QKD) systems since it directly affects the performance of practical system including processing speed, secret key rate, and maximal transmission distance. In this paper, we proposed a novel initial decoding message computation method for multidimensional reconciliation with low density parity check code, which does not need the norm information from the encoder. Both theoretical analysis and simulation results demonstrate that the improved scheme can greatly decrease the communication traffic and storage resource consumption of the reconciliation procedure almost without degradation in the reconciliation efficiency. What is more, the improved scheme can decrease the secure key consumption for classical channel authentication, then increase the secure key rate, and also be conducive to the realization of high-speed CV-QKD systems.

An improved multidimensional reconciliation algorithm for continuous-variable quantum key distribution

Historically, the information efficiency of the secret key in quantum key distribution (QKD) schemes based on binary signal formats was limited to 1 bit/particle. An efficient high-dimensional QKD protocol based on qudits transmission with the quantum Fourier transform is proposed. In the proposal, the inherent encoding framework provides a secure solution to key distribution, where the secret information can be hidden into the relative phases of the generated high-dimensional entangled state by performing the quantum Fourier transform and the quantum controlled-NOT gate. After the reverse operations are carried out, the key information can be decoded with the single-particle measurement chosen from two mutually unbiased bases. The secret key taking the form of the high-dimensional quantum state throughout the proposed QKD protocol enables to break the information efficiency limit. Besides, the security of the proposed QKD protocol is guaranteed by the decoy state method and it is proven to be secure even for the photon number splitting attack and the side-channel attack. The cryptographic performance in terms of security and capacity is better than that of traditional cryptographic protocols.

High-dimensional quantum key distribution based on qudits transmission with quantum Fourier transform

Currently, wearable devices are developing prosperously in the fields of global communication electronic products and personal intelligent terminals, but their information security problem cannot b...

https://journals.sagepub.com/doi/pdf/10.1177/1550147718779678

Quantum solution for secure information transmission of wearable devices

To improve the efficiency of QKD systems, a new QKD protocol based on classical–quantum polarized channels is proposed in this article. By precoding the raw key with polar codes before communication, this protocol has higher code rate and lower time cost compared with the traditional ones. According to the attack strategies that eavesdroppers might employ, we have analyzed the protocol’s security under ideal and practical channel models. We prove that under proper channel parameter setting, the security of this protocol is not lower than BB84 under intercept strategy.

Xiaojun Wen

Papers

An inter-bank E-payment protocol based on quantum proxy blind signature

An improved multidimensional reconciliation algorithm for continuous-variable quantum key distribution

High-dimensional quantum key distribution based on qudits transmission with quantum Fourier transform

Quantum solution for secure information transmission of wearable devices

Efficient quantum key distribution protocol based on classical–quantum polarized channels