Two-Party Quantum Key Agreement Protocol Based on Four-Particle χ State

Abstract

The invention discloses a four-particle x state-based two-party quantum key agreement protocol. The protocol includes following steps that: step 1, Alice and Bob negotiate on quantum-state codes; step 2, Alice prepares n x-state|x<00>>ABCD, and divides all the particles into four ordered sequences, and selects out 2m decoy photons and inserts the decoy photons into the sequences and transmits the sequences to Bob; step 3, Bob measures corresponding decoy photons with a correct measurement base, and informs Alice of measurement results; Alice compares the measurement results and the initial states of the decoy photons, and calculates an error rate, and executes step 4 if the error rate is low, otherwise, executes step 2; and step 4, Alice performs Bell measurement on the particles, Bob executes Z convolution Z-base measurement on the sequences, and Alice and Bob both obtain a shared key. The protocol of the invention can resist existing participant attacks, external attacks and Troy Trojan horse attacks; and the protocol is safe in a noise-free quantum channel and a quantum noise channel. The quantum bit efficiency of the protocol of the invention is higher than that of an existing secure multi-particle entangled state-based quantum key agreement protocol.

Description

technical field

[0001] The invention belongs to the field of quantum communication, and in particular relates to a quantum key agreement (Quantum key agreement) protocol, in particular to a two-party quantum key agreement agreement based on a four-particle χ state. Background technique

[0002] Quantum cryptography is a new technology for communication and network security, and its security is guaranteed by the basic principles of quantum mechanics. Unlike traditional cryptography, which is mostly computationally secure, quantum cryptography can achieve unconditional security, which has attracted a lot of attention. The quantum key agreement (QKA) protocol is a new important branch of quantum cryptography, which allows participants to negotiate a classical shared secret key through an open quantum channel, and the contribution of each participant is the same, any participant None or a subset of participants can independently determine the shared secret. Using the shared se...

Examples

Embodiment Construction

[0023] 1. Preliminary knowledge

[0024] As we all know, {|0>,|1>} forms the Z basis, and {|+>,|->} forms the X basis, where The four Bell states are defined as follows:

[0025]

[0026]

[0027] They form a set of completely orthogonal basis of four-dimensional Hilbert space, namely Bell basis. The χ state is the maximum entangled state of four particles, and they can form a set of completely orthogonal basis of 16-dimensional Hilbert space. In the protocol of the present invention, we use the following χ state as the quantum information source, namely

[0028]

[0029] According to the expression, if for the χ state |χ 00 > ABCD Bell measurements are performed on particles A and B, and on particles C and D basis measurement, the system collapses to the state |φ with probability 1 / 4 + > AB |00> CD ,|ψ - > AB |01> CD ,|ψ + > AB |10>CD and |φ - > AB |11> CD .

[0030] 2. The two-party quantum key agreement protocol based on the four-particle χ sta...

technical field

[0001] The invention belongs to the field of quantum communication, and in particular relates to a quantum key agreement (Quantum key agreement) protocol, in particular to a two-party quantum key agreement agreement based on a four-particle χ state. Background technique

[0002] Quantum cryptography is a new technology for communication and network security, and its security is guaranteed by the basic principles of quantum mechanics. Unlike traditional cryptography, which is mostly computationally secure, quantum cryptography can achieve unconditional security, which has attracted a lot of attention. The quantum key agreement (QKA) protocol is a new important branch of quantum cryptography, which allows participants to negotiate a classical shared secret key through an open quantum channel, and the contribution of each participant is the same, any participant None or a subset of participants can independently determine the shared secret. Using the shared se...

Examples

Embodiment Construction

[0023] 1. Preliminary knowledge

[0024] As we all know, {|0>,|1>} forms the Z basis, and {|+>,|->} forms the X basis, where The four Bell states are defined as follows:

[0025]

[0026]

[0027] They form a set of completely orthogonal basis of four-dimensional Hilbert space, namely Bell basis. The χ state is the maximum entangled state of four particles, and they can form a set of completely orthogonal basis of 16-dimensional Hilbert space. In the protocol of the present invention, we use the following χ state as the quantum information source, namely

[0028]

[0029] According to the expression, if for the χ state |χ 00 > ABCD Bell measurements are performed on particles A and B, and on particles C and D basis measurement, the system collapses to the state |φ with probability 1 / 4 + > AB |00> CD ,|ψ - > AB |01> CD ,|ψ + > AB |10>CD and |φ - > AB |11> CD .

[0030] 2. The two-party quantum key agreement protocol based on the four-particle χ sta...

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