Efficient decoy-state quantum key distribution with quantified security

Security in quantum cryptography [1, 2] is continuously challenged by inventive attacks [3][4][5][6][7] targeting the real components of a cryptographic setup, and duly restored by new countermeasures [8][9][10] to foil them. Due to their high sensitivity and complex design, detectors are the most frequently attacked components. Recently it was shown that two-photon interference [11] from independent light sources can be exploited to avoid the use of detectors at the two ends of the communication channel [12,13]. This new form of detection-safe quantum cryptography, called Measurement-Device-Independent Quantum Key Distribution (MDI-QKD), has been experimentally demonstrated [13][14][15][16][17][18], but with modest delivered key rates.Here we introduce a novel pulsed laser seeding technique to obtain high-visibility interference from gain-switched lasers and thereby perform quantum cryptography without detector vulnerabilities with unprecedented bit rates, in excess of 1 Mb/s. This represents a 2 to 6 orders of magnitude improvement over existing implementations and for the first time promotes the new scheme as a practical resource for quantum secure communications. * marco.lucamarini@crl.toshiba.co.uk arXiv:1509.08137v2 [quant-ph] In Quantum Cryptography, a sender Alice transmits encoded quantum signals to a receiver Bob, who measures them and distils a secret string of bits with the sender via public discussion [1].Ideally, the use of quantum signals guarantees the information-theoretical security of the communication [2]. In practice, however, Quantum Cryptography is implemented with real components, which can deviate from the ideal description. This can be exploited to circumvent the quantum protection if the users are unaware of the problem [19].Usually the most complex components are also the most vulnerable. Therefore the vast majority of the attacks performed so far have targeted Bob's single photon detectors [3][4][5][6][7]. 13] is a recent form of Quantum Cryptography conceived to remove the problem of detector vulnerability. As depicted in Fig. 1(a), two light pulses are independently encoded and sent by Alice and Bob to a central node, Charlie. This is similar to a quantum access network configuration [20], but in MDI-QKD the central node does not need to be trusted and could even attempt to steal information from Alice and Bob. To follow the MDI-QKD protocol, Charlie must let the two light pulses interfere at the beam splitter inside his station and then measure them. The result can disclose the correlation between the bits encoded by the users, but not their actual values, which therefore remain secret. If Charlie violates the protocol and measures the pulses separately, he can learn the absolute values of the bits, but not their correlation. Therefore he cannot announce the correct correlation to the users, who will then unveil his attempt through public discussion.Irrespective of Charlie's choice, the users' apparatuses no longer need a detector and the detection vulnerability of Quantum Cryp...

show abstract

“…

…”

mentioning

confidence: 99%

“…Therefore the vast majority of the attacks performed so far have targeted Bob's single photon detectors [3][4][5][6][7]. 13] is a recent form of Quantum Cryptography conceived to remove the problem of detector vulnerability.…”

mentioning

confidence: 99%

Quantum key distribution without detector vulnerabilities using optically seeded lasers

Comandar¹,

Lucamarini²,

Fröhlich³

et al. 2016

Nature Photon

Self Cite

238

189

View full text Add to dashboard Cite

show abstract

“…These values are obtained through real-time data-processing, including error correction and privacy amplification, on a sifted block size of 1×10 8 bits. The block size is sufficiently large to achieve 85% of the asymptotic secure key rate [26]. Each data block is collected over a session time of about 36 seconds with a sifted bit rate of ~2.7 Mb/s.…”

Section: Resultsmentioning

confidence: 99%

“…We use a QKD system operating with a clock rate of 1 GHz and using the T12 decoy-state protocol [26]. The photons are detected with InGaAs avalanche photodiodes operating in Geiger mode and with self-differencing [27] electronics.…”

Section: Qkd/data Spatial Multiplexing Setupmentioning

confidence: 99%

Quantum key distribution over multicore fiber

Dynes¹,

Kindness²,

Tam³

et al. 2016

Opt. Express

Self Cite

View full text Add to dashboard Cite

Abstract:We present the first quantum key distribution (QKD) experiment over multicore fiber. With space division multiplexing, we demonstrate that weak QKD signals can coexist with classical data signals launched at full power in a 53 km 7-core fiber, while showing negligible degradation in performance. Based on a characterization of intercore crosstalk, we perform additional simulations highlighting that classical data bandwidths beyond 1Tb/s can be supported with high speed QKD on the same fiber. References and links

show abstract

“…Similar to the QBER effects, afterpulses increase gains of the decoy1 and decoy2 pulses, especially decoy2, more than half of its gain comes from afterpulses. Finally, an average secure key rate of 306k bits/s is achieved with a failure probability of 10 −10 [24].…”

mentioning

confidence: 99%

Practical gigahertz quantum key distribution robust against channel disturbance

Wang¹,

Chen²,

Yin³

et al. 2018

Opt. Lett.

View full text Add to dashboard Cite

Quantum key distribution (QKD) provides an attractive solution for secure communication. However, channel disturbance severely limits its application when a QKD system is transfered from the laboratory to the field. Here, a high-speed Faraday-Sagnac-Michelson QKD system is proposed that can automatically compensate for the channel polarization disturbance, which largely avoids the intermittency limitations of environment mutation. Over a 50-km fiber channel with 30-Hz polarization scrambling, the practicality of this phase-coding QKD system was characterized with an interference fringe visibility of 99.35% over 24 hours, and a stable secure key rate of 306k bits/s over 7 days without active polarization alignment.Quantum key distribution (QKD) allows two remote parties (named Alice and Bob) to share secure keys in the presence of an eavesdropper. Its unconditional security is guaranteed by the fundamental laws of quantum physics. As the first commercial application of quantum physics at the single-quantum level [1], the practicality of QKD becomes important when we transfer a QKD system from the laboratory to the field. Contrary to laboratory conditions, field environments are complex and volatile, which would continually interrupt or even terminate the operation of QKD [2-9], and would severely limit its application.In QKD systems deployed over telecom fiber networks, the field environments typically break down into two parts: operating conditions of QKD units, and environments of installed fiber channels that are used to transmit quantum states. By careful design, the operating conditions of QKD units can be well controlled, i.e., isolated from complex environments. While, the environments of installed fiber channels are uncontrollable and ever-changing, quantum states are inevitably disturbed during transmission in fiber channels. More crucially, channel disturbance induced by the external environment accumulates with distance [10]. Due to volatile field environments, variations in optical path length (or time * weich@ustc.edu.cn † yinzq@ustc.edu.cn delay) and fiber channel birefringence [7][8][9][10] are two obstacles preventing long-term continuous operation of QKD systems. However, optical path length variations in fiber channels are relatively slow and could be well tracked [8] or compensated [7] with simple synchronization schemes. Thus, birefringence variations in fiber channels become the most challenging channel disturbance in practical QKD systems. Channel disturbance countermeasures in QKD systems can be classified into active and passive categories. In QKD systems employing active countermeasures, polarization basis alignment modules are added to compensate for birefringence variations in fiber channels [8][9][10] and are essential for low quantum bit error rate (QBER). In QKD systems adopting passive countermeasures, birefringence variations in fiber channels can be automatically compensated, which largely avoid the intermittency limitations of environment mutation. The âĂĲPlug-and-PlayâĂİ system ...

show abstract

Efficient decoy-state quantum key distribution with quantified security

Cited by 179 publications

References 50 publications

Quantum key distribution without detector vulnerabilities using optically seeded lasers

Quantum key distribution without detector vulnerabilities using optically seeded lasers

Quantum key distribution over multicore fiber

Practical gigahertz quantum key distribution robust against channel disturbance

Contact Info

Product

Resources

About