77 results about "Quantum secure direct communication" patented technology

The invention provides a method and a system for anti-interference quantum secure direct communication. The method comprises the following steps that: a sending end performs non-orthogonal state combination coding, randomly expands a bit to two bits, randomly selects two different base combinations, converts the two bits into corresponding quantum states in the base combinations and then sends the two bits through a quantum channel; and a receiving end randomly selects two same base combinations for quantum state measurement so as to realize definite measurement on one bit. The method and the system can effectively solve the problem of quantum secure direct communication under the condition of not accurate measurement on the quantum, and realize point-to-multipoint quantum information distribution.

According to quantum steganography, the classical steganography and quantum secure communication are combined together, and the quantum steganography is popularized in the field of quanta. The quantum steganography aims to realize secret transmission of classified information by utilizing a quantum hidden channel. The invention provides a quantum steganography protocol based on gigahertz (GHZ) state dense coding and entanglement exchange. A hyper-quantum channel of the protocol is formed by establishing the hidden channel on a quantum secure direct communication (QSDC) protocol. The classified information is transmitted by combining the GHZ state dense coding and GHZ state entanglement exchange based on the original QSDC. The capacity of the hyper-quantum channel of the protocol reaches 6-bit per round in covert communication. In addition, the protocol has high imperceptibility and high safety.

The invention discloses a controlled quantum security direct communication method based on four particle cluster states. Alice and Bob respectively serve as a legal information sender and a legal information receiver during a quantum communication process, and Charlie serves as a credible scheme control party; information security is achieved by randomly inserting a single photon to perform measurement-based comparison detection, and communication starts after security detection; Alice uniformly divides the prepared four particle cluster states into two groups, after being subjected to an XOR operation with a pseudorandom sequence, the sent information is encoded on the two particles reserved by Alice via unitary transformation. Alice performs Bell-based measurement on reserved particles, and sends measurement information to Bob, and Bob recovers the original sequence via an initial state sent by Charlie after the measurement information is compared. The four particle cluster states used by the method has good entanglement, connectivity and damage resistance, only the receiver Bob in the method gets the permission of the controller Charlie, Bob can recover the original information, so that the information can be effectively prevented from being attacked during a transmission process, and an implementation process is simple.

The invention discloses a quantum secure direct communication protocol based on the three-particle GHZ entangled state. Alice prepares N groups of particles in the GHZ entangled state, and a sequence C'2 is sent to Bob; the Bob conducts single practical measurement on a sequence A21 and a sequence B21, the Alice conducts single practical measurement on a sequence C21, and it is determined that wiretapping exists if results of two measurements do not meet the corresponding relation; if the results of the two measurements meet the corresponding relation, A1 and B1 are encoded, particles in a sequence A22 and a sequence B22 are inserted into the A1 and the B1, the order of the particles is disrupted, and a sequence C'3 is generated and sent to the Bob; the Bob conducts single practical measurement on the sequence A22 and the sequence B22, the Alice conducts single practical measurement on a sequence C22, and it is determined that wiretapping exists if results of two measurements do not meet the corresponding relation; if the results of the two measurements meet the corresponding relation, the Bob conducts combined measurement on the A1, the B1 and a C1, and the information sent by the Alice is obtained. According to the quantum secure direct communication protocol based on the three-particle GHZ entangled state, the QSDC communication safety can be effectively improved, and the error detection rate reaches up to 62.5%.

The invention discloses a three-party quantum secure direct communication method based on a hyper-entangled Bell state, including the following steps: a user 1 randomly prepares N hyper-entangled Bellstates and splits the Bell states into two sequences; the user 1 encodes a first sequence path and sends the path to a user 2; the user 2 encodes the path after confirming that no eavesdropping exists and sends the path to a user 3; the user 3 notifies the user 1 to send a second sequence after confirming that no eavesdropping exists; the user 1 performs polarization encoding on the second sequence and sends the second sequence to the user 3; the user 3 performs polarization encoding on the second sequence, performs joint hyper-entangled Bell state measurement on the two sequences, and publishes measurement results; the user 1 acquires encoding information of the user 2 and the user 3 respectively; the user 1 announces an initial state Ri and the encoding information R of the user 3 on XOR of the user 2; and the users 2 and 3 acquire the encoding information of the other two parties. According to the scheme of the invention, the transmission is only performed for three times, the probability of photon loss caused by channel loss can be greatly reduced, the security detection can be provided, and the security of transmission can be fully improved.

The invention belongs to the field of quantum security communication, and discloses a semi-quantum secure direct communication method and system based on a Bell state. Two users participate in the execution of a present protocol, the first participating user has advanced quantum functions, can prepare the Bell state, and can use a Bell base to measure a quantum state and has a quantum storage function; the second participating user only has basic quantum functions, specifically: measurement: using a classical base {|0), |1)} to measure quanta, generating a quantum |1) (|0)) in an opposite state according to a measurement result |0) (|1) ), and sending the quantum; reflection: after receiving the quantum, directly sending the quantum to a sender without any modification; and disorder: disturbing the sending sequence of the quantum sequence by using the delay technology. The protocol proposed by the invention is a semi-quantum secure direct communication protocol, which improves the communication efficiency of the protocol while ensuring the absolute security of secret information transmission.

The invention belongs to the technical field of quantum block chains. The invention discloses a quantum block chain network anonymous election method and system based on trust evaluation. The method comprises the following steps: identity trust evaluation of voters among miner nodes is completed by using a quantum secure direct communication technology, then voters calculate commitment values of voter election contents by using a quantum bit commitment protocol, and broadcast the commitment values to all miner nodes in a block chain; and then the miner nodes are combined with a quantum honestyByzantine protocol to complete voting statistics. The security model analysis of the protocol proves that the protocol has the advantages of anonymity, tamper resistance, verifiability and the like;according to the invention, the honesty quantum Byzantine protocol is adopted, so that the blockchain system can achieve a consistency protocol, and the protocol efficiency is better.

The invention belongs to the technical field of safety communication, and discloses a controlled quantum safe and direct communication method and system for preventing tampering. A receiving end is controlled to obtain secret information of a sending end, and the sending end sends SC* to a control end; the control end disorganizes photons in SC*; then the control end sends rearranged SC* to the receiving end; if the control end does not tell the accurate sequence of the photons to the receiving end, the receiving end cannot resume SC and decrypt the secret information; the control end cannot know the secret information encrypted through K(k1, k2, ..., kN). The premise that a controller is honest is not needed; even under the condition that the controller is dishonest, the proposed protocolis still safe, and any tampering of the secret information can be easily found. By means of the controlled quantum safe direct communication method and system for preventing tampering, attack of fakephotons based on quantum teleportation can be resisted, and meanwhile, identities of two participants, namely, the sender and the receiver, can also be verified.

The invention discloses a controlled quantum secure direct communication method based on Huffman compression coding, which is characterized in that a sender Alice and a receiver Bob design the same sequence generator, a control party Charlie enables the two communication parties to generate the same pseudo-random sequence through sending the initial state of the sequence generators; the sender Alice performs compression on the original information by using Huffman compression coding, and carries out an exclusive-or operation on the compressed sequence and the pseudo-random sequence to form a sequence S1; the sender Alice sends a sequence SB to the receiver Bob to detect the channel security, if the channel is secure, the sender Alice divides the sequence S1 into an odd sequence and an even sequence, and the odd sequence the even sequence are differently coded, then loaded to remaining particles SA and sent to the receiver Bob; and if not, the communication is abandoned. The receiver Bob measures decoding and recovers the sequence S1 after detecting the channel security, and performs an exclusive-or operation on the sequence S1 and the pseudo-random sequence to obtain a compressed sequence, and the receiver Bob decompresses the compressed sequence to acquire the original information. The transmission efficiency of quantum secure direct communication can be effectively improved according to the method disclosed by the invention.

The invention discloses a quantum dialogue method irrelevant to measuring equipment based on super-entanglement. The method comprises the following steps that two communication parties randomly prepare a super-entanglement state and a single photon respectively to form corresponding photon sequences; the third detection party performs hyper-entangled Bell state measurement on the photon sequence sent by the communication party and publishes a measurement result, and the communication party performs security detection according to the measurement result; two communication parties simultaneouslyencode information at different degrees of freedom and randomly perform security detection encoding, and the process is similar to quantum secure direct communication at different degrees of freedom;and the two communication parties send the coded photon sequence to the detection party, the detection party performs hyper-entangled Bell state measurement again and publishes a result, and the communication party decodes information according to the result to complete dialogue. According to the method, bidirectional quantum secure direct communication can be realized, communication efficiency is effectively improved, meanwhile, security holes related to measurement equipment and information leakage can be eliminated, and the method has relatively high flexibility, i.e., information codes ondifferent degrees of freedom do not influence each other.

The invention relates to fault tolerance single photon communication technology, and in particular to a multi-channel frequency coding technology based on single photon detection with laser light as an information carrier. Laser light undergoes frequency modulation at a transmitting end and is loaded with information. After channel transmission, the intensity of the laser light attenuates to a single photon magnitude, and the laser light is measured by a single photon detector at a receiving party, and the detected single photon pulse sequence undergoes Fourier transformation so as to extract frequency information. According to the invention, the system has very strong fault tolerance in terms of channel loss and noise. The system addresses the problem of information loss and errors that are caused by channel loss and noise in long-distance laser communication and quantum communication, and provides technical means for the realization of satellite-ground laser communication and quantum secure direct communication.

The embodiment of the invention provide a quantum secure direct communication system irrelevant to a measurement device. The quantum secure direct communication system comprise a transmitting end, a receiving end, and a third party, wherein the transmitting end and the receiving end respectively prepare a first photon sequence and a third photon sequence for security detection and send the first photon sequence and the third photon sequence to the third party for measurement, then the transmitting end and the receiving end perform security detection according to the measurement results, afterthe security detection is passed, the transmitting end loads information to be transmitted into a pre-constructed second photon sequence and sends the information to be transmitted to the third party,the receiving end sends a fourth photon sequence to the third party, and the third party sends the measurement results of the second photon sequence and the fourth photon sequence to the receiving end to complete a communication process, wherein the first photon sequence and the second photon sequence comprise mutually entangled photon pairs; and the third photon sequence and the fourth photon sequence comprise mutually entangled photon pairs. The quantum secure direct communication system provided by the invention can avoid security vulnerabilities caused by a detection device under the premise of ensuring the communication security.

The invention discloses a quantum secure direct communication method based on photon orbital angular momentum coding, comprising the following steps: constructing two unitary operators and giving two groups of complete intrinsic quantum states; when quantum secure direct communication is carried out, based on an intrinsic quantum state space, randomly preparing, by a receiving party, a group of photon sequences, and sending to a sending party; randomly choosing, by the sending party, a check photon from the photon sequences to measure Z<^>p or X<^>p and comparing a measurement basis and a measurement result by a public channel; judging whether a communication channel is secure according to an error rate of the measurement result; if the channel is secure, carrying out coding operation on the photons by the sending party; measuring the received photons by the receiving party, comparing an initial state and a final state of a photon orbital angular momentum, obtaining the coding operation carried out by the sending party and constructing coded logic bit information sent by the sending party. According to the method disclosed by the invention, by using the photon orbital angular momentum coding, the communication capacity and the spectral efficiency of the quantum secure direct communication are improved.

The invention provides a continuous variable-based two-step quantum secure direct communication method. The method comprises the steps that a sending party selects a squeezed operator S(r) randomly toprepare two-mode squeezed light S and S, sends detection light S to a receiving party to perform channel detection and identity authentication; after the channel is confirmed secure and identity authentication is finished, the sending party codes information on signal light S through block transmission and sends the signal light to the receiving party, and the receiving party comparesdetection bits in information blocks so as to recover an original information sequence. Identity authentication is finished during channel detection, so that attach by an intermediary is prevented effectively; and in the information transmission stage, the receiving party determines eavesdropping through detection bits, secret information can be obtained in amplitude and phase of a beam through joint measurement, and the communication efficiency reaches 100%.