5 results about "Alice and Bob" patented technology

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 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 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.

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 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.