25 results about "Alice and Bob" patented technology

A system and method for providing quantum entanglement-as-a-service and simultaneously producing verifiably random sequences of numbers are described. When distributing quantum entanglement between customers Alice and Bob, Alice and Bob may exchange information pertaining to a measurement basis that they respectively used when performing measurements using respective halves of entangled particles. When customer Alice, for example, determines that both Alice and Bob have performed a given measurement in a same measurement basis, said result may be used in a quantum key distribution (QKD) code. When customer Alice determines that they have not performed the given measurement in the same measurement basis, Alice may concatenate said portion of the results into a private and verifiable sequence of random numbers. Providing distributed quantum entanglement therefore results in both a QKD code between said customers and in respective private and verifiably random sequences of numbers.

The present invention relates to the technical field of communications. Disclosed is a two-party quantum secret magnitude comparison method based on a two-level bell state. The present invention comprises the following steps: step I: protocol participants Alice and Bob respectively possessing their own secret values SA and SB, and Alice and Bob sharing a secure n-bit key KAB=KAB1KAB2KKABn by means of QKD; and step II: Alice and Bob sharing a collision-resistant hash function Hash(.) that is resistant to quantum algorithms, and with the assistance of a semi-trusted third party (TP), Alice and Bob completing the comparison between the magnitudes of the secret values of the two. By means of the present invention, an equality relationship and magnitude relationship between the secret values of the two participants, i.e. Alice and Bob, can be effectively determined; a quantum state prepared by the TP is a two-particle maximally entangled Bell state; and by means of the first eavesdropping detection, the absence of eavesdroppers and the honesty of the TP are verified.

The invention discloses an anti-covert communication design method based on artificial noise assisted interference, and relates to the technical field of wireless communication. The method comprises the following steps: constructing an anti-covert communication system model with a full-duplex receiver; selecting an illegal information transmitter (Alice), an illegal information receiver (Bob) and a monitor (Willie) as entity research objects of the anti-covert communication system model; constructing two optimization problems: converting an anti-covert communication system model into constructing a listener optimal detection error probability optimization problem and an optimal artificial noise setting optimization problem; the optimization problem is simplified; solving an optimization problem; according to the design method, artificial noise (AN) is emitted in Alice and Bob communication environments to realize anti-covert communication, the optimal detection error probability optimization problem and the optimal artificial noise setting optimization problem are realized, the detection error probability at Willie is reduced, and relatively low noise emission power is used.

The present invention discloses a MIMO full-duplex secure communication parameter optimization method, an optimization device, and a communication method based on the optimized parameter setting. The parameter optimization method constructs transmission signals of Alice and Bob, adds artificial noise thereto, and performs power allocation and dimension allocation on the effective signal and the artificial noise according to decision variables. At the same time, based on the singular value decomposition of the channel, a specific expression form of the effective signal and the artificial noise is constructed. MIMO full-duplex communication is performed with the constructed transmission signal, and the received signal of each end is obtained. The optimal power allocation coefficient, power allocation matrix, and signal dimension are obtained with the goal of maximizing the system average confidentiality rate. Communication is performed based on the optimized parameters, and the confidentiality performance of the MIMO full-duplex communication system can be improved from the physical layer.

This invention discloses a dual-field quantum key distribution system, including a Charlie end, an Alice end, and a Bob end; it also discloses a dual-field quantum key distribution method based on the aforementioned dual-field quantum key distribution system. This invention discloses a dual-field quantum key distribution system and method that interferes with the unencoded signal light transmitted back from the Alice and Bob ends at the Charlie end, and feeds back the phase drift based on the interference result to compensate for the phase drift of the encoded signal light during transmission in the optical fiber, achieving phase stability. This allows it to adapt to the operating environment of drastic phase changes in long-distance transmission, improving the stability and efficiency of quantum networks and transmission links.

The invention discloses a hidden multi-party key expansion protocol without an entanglement state and an encryption method, and belongs to the field of quantum cryptography. The method is suitable for a protocol which carries out secret key expansion simultaneously with a receiving party in a hidden manner under the condition that a third party monitors a channel, and comprises three parties of Alice, Bob and Charlie, the Alice is a sending party, and the Bob and the Charlie serve as the receiving party; alice, Bob and Charlie establish a completely synchronous channel containing N time bins, Alice completely controls the noise of the channel so as to cover the sending information, then the sending content is agreed, and the receiving party and the Bob carry out key expansion after measurement. Compared with the prior art, the method has the advantages that an entangled quantum state which is difficult to prepare is not used, the channel structure is optimized, and the key generation efficiency is improved.

The present invention discloses a local active phase compensation method and system applied to MDI-QKD. Compared with conventional active phase compensation schemes, this scheme is dedicated to the measurement device-independent quantum key distribution protocol, and the communication distance is extended to twice the original. Compared with the local active phase compensation scheme that uses a single-photon detector to statistically count photons or measure light intensity, this scheme uses a photoelectric detector to convert the light intensity signal and a specially designed control module to process it. Compared with the compensation scheme of a continuous variable measurement device-independent quantum key distribution system, this scheme is applicable to a discrete variable time-phase encoded measurement device-independent quantum key distribution system. Alice and Bob do not need to additionally use a classical channel to exchange compensation information, the design at the detection relay Charlie is more concise, and at the same time, the working point voltage of the phase modulator is obtained in a short time. While the compensation is fast, the proportion of the QKD stage in the entire communication cycle is greatly increased.

This invention discloses a method and system for implementing a completely reference-frame-independent quantum key distribution protocol, belonging to the field of quantum information technology. Alice and Bob, the communicating parties, randomly select mutually unbiased basis vectors to prepare quantum states and send them to a third party, Charlie. Charlie performs Bell state projection measurements and announces the success. Both parties publish the basis vector information, divide the dataset, and calculate the gain and bit error rate. A 3×3 correlation tensor matrix is ​​constructed and singular value decomposition is performed to obtain three reference-frame-independent singular values. The secure key rate is calculated based on the bit error rate. Finally, key negotiation and security enhancement are performed to extract the secure key. This invention does not require basis vector alignment, completely eliminating the dependence on reference frame calibration. It can still stably generate keys even with basis vector drift, and the amount of information required by eavesdroppers is lower, significantly improving the practicality and security of the quantum key distribution system.

The invention relates to a quantum confidential query system and method based on phase coding, and belongs to the field of quantum communication and quantum cryptography. The system comprises a first key distribution subsystem, a second key generation subsystem and a confidential query subsystem. The method comprises the following steps: 1) a user Alice and a database holder Bob generate a first key sequence by using a first key distribution subsystem, and send the first key sequence to a second key generation subsystem; (2) Alice and Bob dilute the first key sequence into a second key sequence through a second key generation subsystem, and carry out key storage; and 3) the Alice and the Bob call the second secret key sequence through the confidential query subsystem, shift the second secret key sequence, and respectively perform encryption and decryption operations to complete confidential information retrieval. In the quantum confidential query process, the problem of limitation of a polarization coding mode is solved through a phase coding mode, so that the practical process of a quantum confidential query protocol is promoted.

The invention relates to the technical field of quantum identity authentication and quantum key distribution, and provides a quantum identity authentication and key updating method and system, which organically integrates QIA (quantum identity authentication) and QKD (quantum key distribution) protocols adopting the same coding mode (generally two groups of conjugate base codes), and provides two schemes according to different application scenes. In the QIA process, a sender Alice and a receiver Bob share an authentication key in advance, and Alice generates a random binary sequence and encodes a quantum state according to the sequence. Alice and Bob implement reliable identity authentication and secret key distribution through multiple steps by executing a QKD process and retaining related information, and complete identity authentication secret key updating. The quantum identity authentication and key updating generalization method provided by the invention can tolerate channel noise, is more practical than the existing scheme, and provides a new thought and method for further development and application of the quantum communication technology.

The application discloses a kind of quantum teleportation methods based on atom-photon entanglement: step 1: Alice and Bob prepare the atom sequence of different initial state.Step 2: Alice generates reference light pulse and signal light pulse, and is transmitted in channel by time division multiplexing.Step 3: Alice manipulates signal light pulse and atom interaction to produce entangled state, and after transmission by quantum channel, coherent light and the atom of Bob establish entanglement, to complete three-particle entanglement.Step 4: Alice divides atom sequence, and Bob carries out channel security detection.Step 5: after channel security, Alice encodes secret information on information sequence atom and publishes measurement result.Step 6: Alice does Hadamard gate operation to the atom sequence carrying information.Step 7: Bob demodulates secret information.The application makes full use of long decoherence time atom-photon entanglement resources, meets the communication demand of high channel capacity and high link efficiency, and provides a feasible way for constructing large-scale, loss-resistant quantum internet.

The present application relates to a kind of quantum secure query system and method based on phase encoding, belong to quantum communication and quantum cryptography field.The system includes first key distribution subsystem, second key generation subsystem and secure query subsystem.The method steps are:1) user Alice and database holder Bob utilize first key distribution subsystem to generate first key sequence, and send it to second key generation subsystem;2)Alice and Bob dilute first key sequence into second key sequence by second key generation subsystem, and carry out key storage;3)Alice and Bob call second key sequence by secure query subsystem, respectively after shifting, carry out encryption and decryption operation, complete secure information retrieval.The present application solves the limitation problem existing in polarization encoding mode in the process of quantum secure query, to promote the practical process of quantum secure query protocol.

The application discloses a zero-knowledge proof quantum identity authentication method and system, and the authentication method comprises the following steps: setting a proving party as Alice and a verifying party as Bob in communication, setting a judgment function for Alice, and providing the corresponding input and output of the judgment function for Bob; Bob prepares 2K groups of superposition states, and sends one group to Alice; Alice performs a phase inversion operation on the received superposition state in combination with the input and output mapping of the judgment function; Bob performs a phase inversion operation on the function output of the superposition state in hand; Bob measures the results inverted by Alice and Bob respectively through a swap test quantum circuit diagram; Bob sends the remaining K-1 groups of superposition state copies to Alice in turn, and Alice and Bob repeat the inversion calculation and measurement steps; and according to the measurement results, the authenticity of the quantum identity information of Alice is judged; the application guarantees that the two parties can complete identity authentication without leaking other information of themselves, and improves the shortcomings of the traditional quantum identity authentication.

A system for key distribution between a first device 102, Alice, and a second device 104, Bob. Alice and a third device 106 are linked by a unidirectional quantum communication channel (QCC) 108 and a bidirectional classical communication channel (CCC) 110. Alice and device 106 mutually agree a first encryption key, K1. Agreement of K1 may be based on a quantum key exchange protocol comprising device 106 transmitting a set of random symbols over the QCC to Alice and transmitting the basis set used for the random symbols over the CCC. Bob mutually agrees a second key, K2, with device 106 in a similar manner using QCC 112 and CCC 114. Device 106 encrypts K1 with K2 and sends it to Bob. Alice generates a third encryption key, KA, using a random number generator (RNG). KA is encrypted with a previously shared key, KOLD, and sent to Bob over CCC 116. Bob also uses a RNG to generate a fourth encryption key, KB, which is sent to Alice over CCC 116 also using key KOLD. Both Alice and Bob combine K1, KA, and KB to generate a final fifth encryption key, KF, for communication with each other.

The invention relates to the technical field of wireless communication, and particularly discloses a relay unmanned aerial vehicle deployment optimization method and system for covert communication, a relay covert communication system is firstly constructed, the system comprises a transmitting end Alice, a receiving end Bob, an unmanned aerial vehicle (UAV) and a detector Willie, obstacles exist between the Alice and the Bob, the Alice transmits information to the Bob through the UAV, and the Willie monitors the transmission between the Alice and the UAV; further analyzing the limitation of data transmission and concealed transmission among Alice, Bob, Willie and UAV in the relay concealed communication system, taking the maximization of the average throughput C of the relay concealed communication system as an optimization target, and constructing an optimization problem according to constraint conditions in the operation of the relay concealed communication system; and further performing joint solution on the optimization problem to obtain the three-dimensional position of the UAV, the transmitting power PA of the Alice and the amplifier gain AU of the UAV, thereby realizing the deployment of the position of the UAV in covert communication on the basis of ensuring the maximum average throughput of the system and the concealment requirement.

The application discloses a kind of measurement equipment independent quantum conversation methods with bidirectional identity authentication function, the method is mutually authenticated whether communication two sides are legal collaborators, then directly utilize quantum channel to mutually converse each other.Communication two sides Alice and Bob mutually share a set of identity keys by BB84 protocol, Alice and Bob are only responsible for preparing entangled photon pair and single photon, and performing encoding operation to photon, all measurement tasks are completed by third party measurement end Charlie.Alice and Bob can verify the identity of two sides according to the Bell state analysis result of Charlie, determine as the legal party of communication, and complete bidirectional communication after that.The application first applies bidirectional identity authentication technology to MDI-QD field, can resist the impersonation attack of eavesdropper, and by completing measurement task by third party, can effectively resist all attacks to imperfect measurement equipment, enhance the security of two-way identity authentication code and communication.The application has very important significance to promote the practical application of quantum conversation.

The invention relates to clock synchronization, in particular to a low-complexity clock offset synchronization method for quantum key distribution, which comprises the following steps: Alice and Bob agree in advance to determine the maximum level of maximum recoverable offset and interleaving degree; the Alice sends a starting signal to the Bob through the data channel; alice generates a synchronization mode and sends the synchronization mode to Bob through a quantum channel; after Bob receives the starting signal, single photon events are collected, and clock skew is recovered by adopting a binary search algorithm; according to the technical scheme provided by the invention, the defects of high calculation complexity, high resource consumption and need of a large amount of information interaction in the prior art can be effectively overcome.

The invention relates to quantum key distribution, in particular to a semi-device independent quantum key distribution method based on a coherence equal game, which comprises the following steps: an untrusted source sends quantum states to Alice and Bob, and the Alice and Bob block or do not block a path through random selection operation; the untrusted server receives a classic detection result transmitted by a blocked path / a quantum state transmitted by a non-blocked path; recording a random selection operation, a classical detection result and a quantum state measurement result, and checking game winning conditions; repeatedly executing a plurality of rounds of protocols, and sharing data through an authentication channel; calculating a game winning rate, and verifying the quantum coherence type according to the game winning rate; estimating single detection violation parameters, and judging whether multi-photon noise is tolerated or not; performing information coordination and privacy amplification to generate a final security key; the technical scheme provided by the invention can effectively overcome the defects that multi-photon noise is difficult to tolerate, complex quantum operation needs to be executed and a side channel attack risk exists.

A method of quantum key distribution making use of 2-qubit entanglement, by which one entangled qubit is sent from an operator O to Alice and the other entangled qubit is sent from operator O to Bob, making for key-sharing among three parties (multi-user quantum key distribution, i.e. MU QKD). Alice and Bob each measures a respective sequence of qubits randomly along either one of two states, records the measurements in a respective list, and encodes the bits in an encoded list. The encoded lists are sent to operator O for entanglement to be verified with the CHSH inequality. Bob's verified list is sent to Alice and vice-versa, allowing Alice and Bob to further verify correlation. Non-entangled bits are rejected until Alice and Bob have a similar key, being a reconciled quantum-based key as sought.

A system and method for providing quantum entanglement-as-a-service and simultaneously producing verifiably random sequences of numbers are described. When distributing quantum entanglement between customers Alice and Bob, Alice and Bob may exchange information pertaining to a measurement basis that they respectively used when performing measurements using respective halves of entangled particles. When customer Alice, for example, determines that both Alice and Bob have performed a given measurement in a same measurement basis, said result may be used in a quantum key distribution (QKD) code. When customer Alice determines that they have not performed the given measurement in the same measurement basis, Alice may concatenate said portion of the results into a private and verifiable sequence of random numbers. Providing distributed quantum entanglement therefore results in both a QKD code between said customers and in respective private and verifiably random sequences of numbers.

The invention relates to quantum key distribution, in particular to a quantum key distribution method based on mixing of an entanglement protocol and a non-entanglement protocol, Alice and Bob respectively generate superposition states and perform measurement, and the entanglement protocol or the non-entanglement protocol is selected according to a measurement result; when the entanglement protocol is selected, generating a first key bit by using the entanglement protocol; when the non-entangled protocol is selected, generating a second key bit by using the non-entangled protocol; performing uniform classical post-processing on the first key bit and the second key bit; s4, repeating the steps S1 to S4 to form two key streams composed of the first key bit and the second key bit, and combining the two key streams based on the expected key length of the combination protocol to obtain a final security key; according to the technical scheme provided by the invention, the defect that the key generation rate and the security are difficult to consider at the same time in the prior art can be effectively overcome.

The application discloses a kind of unmanned aerial vehicle assisted cooperative interference security communication methods in two-way eavesdropping channel, including communication both sides Alice and Bob, eavesdropper Eve and the unmanned aerial vehicle of sending interference signal, the present application relates to the technical field of secure communication.The two-way eavesdropping channel unmanned aerial vehicle assisted cooperative interference security communication, by jointly optimizing the transmission power of both sides in two-way channel, the interference power and flight trajectory of unmanned aerial vehicle maximum security capacity of communication system, the power distribution and flight trajectory optimization scheme under unmanned aerial vehicle cooperative interference assisted security communication system are proposed, and the lower bound of the achievable security rate in the process of unmanned aerial vehicle flight under the constraint of average transmission power and maximum transmission power is obtained, so an effective suboptimal algorithm is proposed using block coordinate descent method and continuous convex optimization, effectively improve the communication security of communication system, jointly optimize legal user power, unmanned aerial vehicle interference power and flight trajectory to prevent eavesdropper from eavesdropping useful information.

A system and method for providing quantum entanglement-as-a-service and simultaneously producing verifiably random sequences of numbers are described. When distributing quantum entanglement between customers Alice and Bob, Alice and Bob may exchange information pertaining to a measurement basis that they respectively used when performing measurements using respective halves of entangled particles. When customer Alice, for example, determines that both Alice and Bob have performed a given measurement in a same measurement basis, said result may be used in a quantum key distribution (QKD) code. When customer Alice determines that they have not performed the given measurement in the same measurement basis, Alice may concatenate said portion of the results into a private and verifiable sequence of random numbers. Providing distributed quantum entanglement therefore results in both a QKD code between said customers and in respective private and verifiably random sequences of numbers.

A system and method for providing quantum entanglement as a service while generating a verifiable sequence of random numbers is described. When quantum entanglement is distributed between clients Alice and Bob, Alice and Bob may exchange information about the measurement bases they respectively use when performing measurements using a corresponding half of the entangled particles. For example, when a customer Alice determines that both Alice and Bob have performed a given measurement on the same measurement basis, the result may be used in a quantum key distribution (QKD) code. When customers Alice determine that they do not perform the given measurement on the same measurement basis, Alice may concatenate the portions of the results into a private and verifiable sequence of random numbers. Thus, providing distributed quantum entanglement produces QKD codes between the customers and produces corresponding private and verifiable sequences of random numbers.

The present invention proposes a TF-QKD method and device using an avalanche detector, which relates to the field of quantum communication technology. Alice and Bob each use single-wavelength optical time division multiplexing to periodically encode phase reference light and quantum signal light, and then transmit them to Charlie. Before the start of TF-QKD, a synchronous clock sends a clock signal to Alice and Bob. Alice and Bob send test pulse signals at preset times. Charlie calibrates and delay-compensates the synchronous clock based on the detection results of the test pulse signals, so that the arrival times of the test pulse signals emitted by Alice and Bob are consistent. The output signal delay from the synchronous clock to the optical switch is adjusted to align the switching time of the optical switch with the encoding period of Alice and Bob. The optical switch controls the phase reference light and quantum signal light to enter different single-photon detectors for detection according to the switching time.