44 results about "BB84" patented technology

A method of user-authenticated quantum key distribution according to the present invention shares a position having the same basis without making public basis information using previously shared secret keys and authenticates a quantum channel by confirming whether there is the same measured outcome at that position, in order to secure unconditional security of BB84 quantum key distribution (QKD) protocols vulnerable to man-in-the-middle attack.

The invention relates to the field of quantum communication, in particular to a quantum key distribution device capable of configuring multiple protocols, which utilizes a simplified Faraday Michelsoninterference ring combined with an intensity modulator to finish timestamp coding in a chopping mode. Phase modulation is completed through a Sagnac ring device composed of a single-polarization phase modulator, a polarization beam splitter and a Faraday rotator, so that the purpose of composite encoding and decoding is achieved, and the quantum key distribution device capable of configuring multiple protocols and multiple decoy state schemes is achieved. The device can be compatible with various protocols including a BB84 protocol, a reference system independent protocol, a six-state protocol, a SARG protocol and the like, and has the characteristics of phase modulation polarization independence, low system complexity and the like.

Systems and methods for obtaining information on a key in the BB84 (Bennett-Brassard 1984) protocol of quantum key distribution are provided. A representative system comprises a quantum cryptographic entangling probe, comprising a single-photon source configured to produce a probe photon, a polarization filter configured to determine an initial probe photon polarization state for a set error rate induced by the quantum cryptographic entangling probe, a quantum controlled-NOT (CNOT) gate configured to provide entanglement of a signal with the probe photon polarization state and produce a gated probe photon so as to obtain information on a key, a Wollaston prism configured to separate the gated probe photon with polarization correlated to a signal measured by a receiver, and two single-photon photodetectors configured to measure the polarization state of the gated probe photon.

The invention discloses a quantum key distribution networking system and a quantum key distribution method. The system comprises: a first quantum state preparation sending end, a second quantum state preparation sending end and a measuring end, and the quantum state preparation includes: a light source , an intensity modulator, a phase encoder and an adjustable attenuator; the phase encoder is used to modulate each optical pulse according to the target phase encoding mode, so that each optical pulse is divided into two pulses with a target delay, and modulated The phase difference of the two pulses; the phase decoder in the measurement end is used to modulate the phase difference of the two pulses; the polarization controller modulates the polarization state of the light quantum input by the first fiber channel when executing the first target protocol mode. The phase difference between the two pulses is modulated by the phase decoder, which eliminates the difference between the MDI protocol and the BB84 protocol in encoding and detection, realizes the compatibility of the MDI protocol and the BB84 protocol in the same system, and improves the quantum key distribution. usability of the network.

A sending end, an encoding method, and a quantum communication system for realizing encoding of six polarization states. The present invention relates to a sending end, an encoding method, and a quantum communication system for a quantum communication system, which can use the fewest optical elements and the most A stable way to realize the four polarization state codes commonly used in the preparation of the BB84 protocol, such as H, V, and other two polarization state codes, such as

A polarization state ambiguity elimination method when the evolution reconstruction is incomplete. When the quantum key distribution system is implemented according to the protocol of BB84 using two sets of non-orthogonal bases, the method of the present invention can combine the steps of polarization compensation to eliminate from The ambiguity of the polarization state evolution reconstructed from the measurement results of quantum communication provides accurate historical data for real-time polarization state prediction and compensation.

A detection method for a detector control attack, which is used to detect a detector control attack in a quantum key distribution system, comprising: a sending end sends a quantum state to a receiving end, each detector in the receiving end randomly selects different detection The quantum state is measured, and the measurement results are recorded; according to the measurement results, the count rate and bit error rate detected by the detector are counted, wherein the number of count rate and bit error rate obtained by statistics is at least two; according to the count of the detector Rate and bit error rate and the conditions of normal quantum key distribution of the quantum key distribution system to judge whether the quantum key distribution system is attacked by the detector control. The method and system realize the detection of whether the quantum key distribution system is attacked by the detector control, and do not depend on the defense criterion of the specific detector implementation mode, and do not depend on the coding implementation scheme of the quantum key distribution system. For phase coding and Polarization-encoded BB84-like protocols are applicable.

The invention discloses a polarization encoding device for quantum key distribution, including a laser LD, an optical path selector, a 2X2 polarization encoding device and a beam combiner BC, wherein the 2X2 polarization encoding device has 2 input ports and 2 output ports , the present invention also provides a quantum key distribution system. Compared with the prior art, a polarization encoding device of the present invention adopts a 2X2 polarization encoding module, only needs one phase modulator, and modulates the phase 0 or π to prepare 4 kinds of BB84 polarization states. It can not only solve the problem of inconsistent wavelengths of multiple lasers, but also reduce the requirements on the driving circuit of the phase modulator. It not only ensures the safety of quantum state preparation, but also reduces the complexity of the encoding device.