Key Generation Rate Research Articles

A local pilot auxiliary key generation scheme for secure underwater acoustic communication

To effectively extend physical layer key generation techniques to the underwater acoustic channel, a novel underwater key generation scheme is proposed. First, a local pilot auxiliary wait channel sounding protocol is proposed to solve impaired reciprocity problems caused by the great transmission delay. At the same time, the protocol ensures high key entropy and prevents the nearby eavesdroppers. Second, two traditional enhancing mechanisms are applied to improve the key agreement. Third, an assembly line protocol is proposed to solve the problem that the key generation rate decreases rapidly with the increase of communication distance. Fourth, a double-layer compensation centralized quantization combined with adaptive guard interval quantization method is proposed to improve the rate of key agreement and key generation. Finally, simulation results show that the bit error rate is lower than 0.01, and the key generation rate is higher than 600 bits/s, which verify the superiority of the proposed scheme.

Round-robin-differential-phase-shift quantum key distribution based on wavelength division multiplexing

Most quantum communications are resilient against eavesdropping attacks. But most protocols fail to address the problems of the poor rates of data transmission and key generation with the constraints of transmission distance and misattribution errors. To address these issues, we propose a new round-robin-differential-phase-shift (RRDPS) quantum key distribution (QKD) protocol to improve the transmission and key generation rates, secure transmission distance and misattribution errors. The new protocol named WDM-OAM-MDI-RRDPS QKD protocol is based on a combination of the wavelength division multiplexing (WDM) technique, Fibonacci-valued orbital angular momentum (OAM) theory, decoy state and measurement-device independent (MDI) method. It utilizes a series of coherent weak sources simultaneously and high-capacity Fibonacci-valued encoding technology. In our protocol, WDM technology can greatly increase the amount of information transmitted in optical fiber communication, and improve the transmission efficiency, the total secure bit rate and the key generation rate of QKD. The OAM theory can achieve basis independence and increase the information capacity per photon from one to five. Fibonacci-valued OAM states can be used to reduce misattribution errors. The decoy state and MDI method can be used to increase the transmission distance resilient to the Photon-number-splitting and detector blinding attacks.

Reference-frame-independent measurement-device-independent quantum key distribution using hybrid logical basis

The multiple-qubit logical basis, originally introduced in the context of fault-tolerant quantum computing in decoherence-free subspace (DFS), has specific applications for resolving a reference frame misalignment problem in quantum information protocols. In this paper, an alignment-free MDI-QKD scheme is proposed with rotational-invariant state, which is immune to the collective noise induced by misalignment between two distant legitimate parties. In our protocol, the initial logical qubit is created in the polarization-orbit angular momentum hybrid space, while the transmission is entirely done in the rotation-invariant DFS under the collective noise associated with misalignment. The partial Bell state measurement is performed on the logical qubits to sort the logical Bell state. Compared with the original MDI-QKD protocols, the numerical simulations show that our modified scheme has apparent improvements both in transmission distance and key generation rate. Furthermore, only ordinary optical elements are required in our protocol.

Long-Distance Continuous-Variable Quantum Key Distribution With Quantum Scissors

The use of quantum scissors, as candidates for non-deterministic amplifiers, in continuous-variable quantum key distribution systems is investigated. Such devices rely on single-photon sources for their operation and as such, they do not necessarily preserve the Guassianity of the channel. Using exact analytical modeling for system components, we bound the secret key generation rate for the system that uses quantum scissors. We find that for non-zero values of excess noise such a system can reach longer distances than the system with no amplification. The prospect of using quantum scissors in continuous-variable quantum repeaters is therefore emboldened.

GeneWave: Fast Authentication and Key Agreement on Commodity Mobile Devices

Device-to-device communication is widely used for mobile devices and Internet of Things. Authentication and key agreement are critical to build a secure channel between two devices. However, existing approaches often rely on a pre-built fingerprint database and suffer from low key generation rate. We present GeneWave, a fast device authentication and key agreement protocol for commodity mobile devices. GeneWave first achieves bidirectional initial authentication based on the physical response interval between two devices. To keep the accuracy of interval estimation, we eliminate time uncertainty on commodity devices through fast signal detection and redundancy time cancellation. Then, we derive the initial acoustic channel response for device authentication. We design a novel coding scheme for efficient key agreement while ensuring security. Therefore, two devices can authenticate each other and securely agree on a symmetric key. GeneWave requires neither special hardware nor pre-built fingerprint database, and thus it is easy-to-use on commercial mobile devices. We implement GeneWave on mobile devices (i.e., Nexus 5X and Nexus 6P) and evaluate its performance through extensive experiments. Experimental results show that GeneWave efficiently accomplish secure key agreement on commodity smartphones with a key generation rate 10 $\times$ faster than the state-of-the-art approach.

Nonreciprocity Compensation Combined With Turbo Codes for Secret Key Generation in Vehicular Ad Hoc Social IoT Networks

The physical attributes of the dynamic vehicle-to-vehicle (V2V) propagation channel can be utilised for the generation of highly random and symmetric cryptographic keys. However, in a physical-layer key agreement scheme, non-reciprocity due to inherent channel noise and hardware impairments can propagate bit disagreements. This has to be addressed prior to the symmetric key generation which is inherently important in social Internet of Things (IoT) networks, including in adversarial settings (e.g. battlefields). In this paper, we parametrically incorporate temporal variability attributes, such as three-dimensional (3D) scattering and scatterers mobility. Accordingly, this is the first work to incorporate such features into the key generation process by combining non-reciprocity compensation with turbo codes. Preliminary results indicate a significant improvement when using Turbo Codes in bit mismatch rate (BMR) and key generation rate (KGR) in comparison to sample indexing techniques.

Hybrid quantum key distribution using coherent states and photon-number-resolving detectors

We put forward a hybrid quantum key distribution protocol based on coherent states, Gaussian modulation, and photon-number-resolving (PNR) detectors, and show that it may enhance the secret key generation rate (KGR) compared to homodyne-based schemes. Improvement in the KGR may be traced back to the dependence of the two-dimensional discrete output variable on both the input quadratures, thus overcoming the limitations of the original protocol. When reverse reconciliation is considered, the scheme based on PNR detectors outperforms the homodyne one both for individual and collective attacks. In the presence of direct reconciliation, the PNR strategy is still the best one against individual attacks, but for the collective ones the homodyne-based scheme is still to be preferred as the channel transmissivity decreases.

Quantum key distribution using in-line highly birefringent interferometers

Secure communication networks enabled by commercial quantum key distribution (QKD) are already available. However, their widespread deployment will require great efforts towards reducing the currently prohibitive cost of QKD systems. Here, we propose a compact and cost-effective alternative to the asymmetric Mach-Zehnder interferometer commonly used to implement phase encoding in the Bennett-Brassard 1984 (BB84) QKD protocol. Our solution consists of an all-fiber, in-line, highly birefringent interferometer (HBI). The HBI shows improved tolerance to length mismatches and a simpler assembly, making it particularly desirable for the fabrication of multi-user systems where several interferometers must have matched delays and where cost and space considerations can be most critical, such as quantum access networks. As a proof-of-principle, we demonstrate point-to-point QKD operation with HBIs over 15.5 km drop fiber and an 8-port passive optical network splitter. We achieve a secure key generation rate of 299.4 ± 16.4 kbit/s with a quantum bit error rate of 2.89 ± 0.31% for a continuous 25 h operation period.

High-Agreement Uncorrelated Secret Key Generation Based on Principal Component Analysis Preprocessing

Random and high-agreement secret key generation from noisy wideband channels is challenging due to the autocorrelation inside the channel samples and compromised cross correlation between channel measurements of two keying parties. This paper studies the signal preprocessing algorithms to establish high-agreement uncorrelated secret key in the presence of channel independent eavesdroppers. We first propose a general mathematical model for various preprocessing schemes, including principal component analysis (PCA), discrete cosine transform (DCT) and wavelet transform (WT). Among preprocessing schemes, PCA is proved to achieve the optimal secret key rate. Next, PCA with common eigenvector has been found to outperform PCA with private eigenvector in terms of an overall consideration of key agreement, information leakage, and computational expense. Then, we propose a system level design of key generation, including quantization, information reconciliation, and privacy amplification. Numerical results verify that the key generation enhanced by PCA with common eigenvector can achieve secret key with high key generation rate, low key error rate, and good randomness.

An Investigation of Using Loop-Back Mechanism for Channel Reciprocity Enhancement in Secret Key Generation

Physical layer security key generation exploits unpredictable features from wireless channels to achieve high security, which requires high reciprocity in order to set up symmetric keys between two users. This paper investigates enhancing the channel reciprocity using a loop-back scheme with multiple frequency bands in time-division duplex (TDD) communication systems, in order to mitigate the effect of hardware fingerprint interference and synchronization offset. The scheme is evaluated to be robust to passive eavesdropping and active Man-in-the-Middle attack through both theoretical analyses and practical measurements. A secret key generation protocol is subsequently designed. The performance of the proposed secret key generation method is then evaluated through both numerical simulation and experiments. Results demonstrate that the proposed scheme can effectively mitigate non-reciprocity and outperforms the classical TDD scheme in both key disagreement rate and key generation rate.

Social-Aware Secret Key Generation for Secure Device-to-Device Communication via Trusted and Non-Trusted Relays

Physical layer security (PLS) is a promising technology in device-to-device (D2D) communications by exploiting reciprocity and randomness of wireless channels, which attracts considerable research attention in the D2D communications community. In this paper, we investigated PLS for secure key generation rate (SKGR) in D2D communications based on cooperative trusted and non-trusted relays. By leveraging social ties, we exploit three social phenomena for secure communications, i.e., trusted scenario (social trust), non-trusted scenario (social reciprocity), and partially trusted scenario (mixed social trust and social reciprocity). The coalition game theory is further utilized to select the optimal relay pairs for improving SKGR. On the basis of social ties, we develop an algorithm for SKGR that protects the keys secret from both eavesdropper and non-trusted selected relays. We incorporate secure relays selection and system wide security for D2D communications. The stability and convergence of the proposed algorithm are also proved in this paper. Both numerical and analytical results verify effectiveness and consistency of our proposed scheme, which ensures better SKGR performance in D2D communications.

One-way quantum repeaters with quantum Reed-Solomon codes

We show that quantum Reed-Solomon codes constructed from classical Reed-Solomon codes can approach the capacity on the quantum erasure channel of $d$-level systems for large dimension $d$. We study the performance of one-way quantum repeaters with these codes and obtain a significant improvement in key generation rate compared to previously investigated encoding schemes with quantum parity codes and quantum polynomial codes. We also compare the three generation of quantum repeaters using quantum Reed-Solomon codes and identify parameter regimes where each generation performs the best.

Key Distribution Based on Phase Fluctuation Between Polarization Modes in Optical Channel

This letter proposes and experimentally demonstrates an approach for generating and sharing a secret key based on the random phase fluctuation between orthogonal polarization modes (OPMs). A delay interferometer (DI) is placed to extract the phase differences inside the optical channel, where reconfigurable lengths of polarization-maintaining fiber are applied as the main source of fluctuation. It is proven that the output signals from the DI can generate random and highly correlated waveforms that can be extracted as the key and shared between the two communication parties. Due to the environment-related randomness and channel-dependent uniqueness of phase fluctuation in OPMs, the security enhancement of the proposed scheme is evaluated with the capability against various tapping attacks. As a proof of concept, the key generation rate of 220 bits/s with bit-error rate of 5% is successfully demonstrated over 25-km standard single-mode fiber. Moreover, the proposed scheme has the advantage of low cost, compatible with current optical fiber networks, and suitable for long-distance transmission, since optical amplifiers can be applied.

Passive decoy-state quantum key distribution with the SARG04 protocol

We present a new scheme for realizing passive decoy-state quantum key distribution with the SARG04 protocol. It is based on parametric down-conversion sources, and we do not need to modulate the pumping light into different intensities. By applying local-mode-splitting detections on Alice’s side, legitimate users can obtain four different kinds of counting events on Bob’s side, due to intrinsic correlations between photon pairs from parametric down-conversion processes. In the new scheme, we do not need to modulate signal pulses into different intensities and can, thus, avoid introducing any intensity modulating uncertainty. As a result, quite precise estimations of single- or multi-photon-pulse contributions can be obtained, enabling better performance of the key generation rate and transmission distance compared with other existing SARG04 protocols, e.g., the four-intensity decoy-state method using either parametric down-conversion sources or weak coherent sources. Besides, through comparisons, we also find that the proposed new passive decoy-state SARG04 protocol can also show some superiority over the conventional three-intensity decoy-state BB84 protocol at long transmission distances under certain experimental conditions.

Metropolitan Quantum Key Distribution with Silicon Photonics

Photonic integrated circuits (PICs) provide a compact and stable platform for quantum photonics. Here we demonstrate a silicon photonics quantum key distribution (QKD) transmitter in the first high-speed polarization-based QKD field tests. The systems reach composable secret key rates of 950 kbps in a local test (on a 103.6-m fiber with a total emulated loss of 9.2 dB) and 106 kbps in an intercity metropolitan test (on a 43-km fiber with 16.4 dB loss). Our results represent the highest secret key generation rate for polarization-based QKD experiments at a standard telecom wavelength and demonstrate PICs as a promising, scalable resource for future formation of metropolitan quantum-secure communications networks.

Phase-encoded measurement device independent quantum key distribution without a shared reference frame

In this paper, a phase-encoded measurement device independent quantum key distribution (MDI-QKD) protocol without a shared reference frame is presented, which can generate secure keys between two parties while the quantum channel or interferometer introduces an unknown and slowly time-varying phase. The corresponding secret key rate and single photons bit error rate is analysed, respectively, with single photons source (SPS) and weak coherent source (WCS), taking finite-key analysis into account. The numerical simulations show that the modified phase-encoded MDI-QKD protocol has apparent superiority both in maximal secure transmission distance and key generation rate while possessing the improved robustness and practical security in the high-speed case. Moreover, the rejection of the frame-calibrating part will intrinsically reduce the consumption of resources as well as the potential security flaws of practical MDI-QKD systems.

A self-adjusting quantum key renewal management scheme in classical network symmetric cryptography

Quantum private communication is a technology for secure communication that uses the laws of quantum mechanics to distribute quantum keys for encryption. Currently it has been widely used in the classical network symmetric cryptography environments. When we perform encrypted transmission of Internet multimedia data by using quantum keys, it is important to make full use of the characteristics of the quantum key in its renewal and consumption management. Researchers have already proposed a number of solutions. In this article, a novel self-adjusting quantum key renewal management scheme is proposed. It uses the detected quantum network status information of the QBER, which is also related to the final quantum key generation rate in the quantum network. A sliding window mechanism is introduced to manage quantum key renewal rate. The quantum key is then used as the secret key for classic encryption algorithms such as AES to encrypt network traffic. A set of experiments were performed in a real QKD environments to show that, compared with current quantum key renewal management schemes, the proposed scheme allows the dynamic management of quantum key renewal rate and it can effectively enhance network security and improve the security of existing Internet multimedia data transmission.

Passive measurement-device-independent quantum key distribution with orbital angular momentum and pulse position modulation

Based on the orbital angular momentum and pulse position modulation, we present a novel passive measurement-device-independent quantum key distribution (MDI-QKD) scheme with the two-mode source. Combining with the tight bounds of the yield and error rate of single-photon pairs given in our paper, we conduct performance analysis on the scheme with heralded single-photon source. The numerical simulations show that the performance of our scheme is significantly superior to the traditional MDI-QKD in the error rate, key generation rate and secure transmission distance, since the application of orbital angular momentum and pulse position modulation can exclude the basis-dependent flaw and increase the information content for each single photon. Moreover, the performance is improved with the rise of the frame length. Therefore, our scheme, without intensity modulation, avoids the source side channels and enhances the key generation rate. It has greatly utility value in the MDI-QKD setups.

Optimized decoy state QKD for underwater free space communication

Quantum cryptography (QC) is envisioned as a solution for global key distribution through fiber optic, free space and underwater optical communication due to its unconditional security. In view of this, this paper investigates underwater free space quantum key distribution (QKD) model for enhanced transmission distance, secret key rates and security. It is reported that secure underwater free space QKD is feasible in the clearest ocean water with the sifted key rates up to 207[Formula: see text]kbps. This paper extends this work by testing performance of optimized decoy state QKD protocol with underwater free space communication model. The attenuation of photons, quantum bit error rate and the sifted key generation rate of underwater quantum communication is obtained with vector radiative transfer theory and Monte Carlo method. It is observed from the simulations that optimized decoy state QKD evidently enhances the underwater secret key transmission distance as well as secret key rates.

Measurement-device-independent quantum key distribution with multiple crystal heralded source with post-selection

The multiple crystal heralded source with post-selection (MHPS), originally introduced to improve the single-photon character of the heralded source, has specific applications for quantum information protocols. In this paper, by combining decoy-state measurement-device-independent quantum key distribution (MDI-QKD) with spontaneous parametric downconversion process, we present a modified MDI-QKD scheme with MHPS where two architectures are proposed corresponding to symmetric scheme and asymmetric scheme. The symmetric scheme, which linked by photon switches in a log-tree structure, is adopted to overcome the limitation of the current low efficiency of m-to-1 optical switches. The asymmetric scheme, which shows a chained structure, is used to cope with the scalability issue with increase in the number of crystals suffered in symmetric scheme. The numerical simulations show that our modified scheme has apparent advances both in transmission distance and key generation rate compared to the original MDI-QKD with weak coherent source and traditional heralded source with post-selection. Furthermore, the recent advances in integrated photonics suggest that if built into a single chip, the MHPS might be a practical alternative source in quantum key distribution tasks requiring single photons to work.