Quantum entity authentication apparatus and method

1. A quantum entity authentication apparatus of a first entity, comprising:

at least one processor; and memory having instructions stored thereon, which, when executed by the at least one processor, cause the at least one processor to function as:

a quantum state preparation unit for preparing an authentication quantum state that is generated based on an authentication key previously shared with a second entity;

a quantum channel verification unit for transmitting a quantum state, generated by performing an operation using a prestored unique operator on the authentication quantum state, to a quantum measurement device, and for verifying security of a quantum channel by using a result of Bell measurement and the authentication quantum state, the result of the Bell measurement being revealed by the quantum measurement device for the quantum state; and

a quantum entity authentication unit for, when the security of the quantum channel is verified, authenticating the second entity using the result of the Bell measurement and the unique operator,

wherein the quantum state preparation unit separates the authentication quantum state into a verification state for verifying the security of the quantum channel and an authentication state for authenticating the second entity,

wherein the quantum channel verification unit verifies the security of the quantum channel depending on whether a quantum state, generated by performing the operation using the unique operator on the verification state, and a quantum state of the second entity match the result of the Bell measurement,

wherein the quantum entity authentication unit authenticates the second entity depending on whether a quantum state, generated by performing the operation using the unique operator on the authentication state, and the quantum state of the second entity match the result of the Bell measurement.

2. The quantum entity authentication apparatus of claim 1 , wherein the verification state is configured such that an operation in which a Hadamard operator is included in the unique operator is performed on the verification state.

3. The quantum entity authentication apparatus of claim 1 , wherein the quantum measurement device reveals a result of Bell measurement by a detector reacting to an input quantum state, among multiple detectors, using a polarization beam splitter that receives the input quantum state.

4. The quantum entity authentication apparatus of claim 3 , wherein the quantum measurement device is configured to, when two quantum states are input, decompose the two quantum states into four Bell states, and reveal the result of the Bell measurement from which coincidence measurement events in any one detector are excluded.

5. The quantum entity authentication apparatus of claim 1 , wherein the quantum channel verification unit receives a location of the verification state from the second entity and transmits information about a unique operator used to perform an operation at the location of the verification state to the second entity.

6. The quantum entity authentication apparatus of claim 5 , wherein the quantum entity authentication unit receives a location of the authentication state from the second entity and transmits information about the unique operator used to perform an operation at the location of the authentication state to the second entity.

7. The quantum entity authentication apparatus of claim 6 , wherein the second entity authenticates an additional entity that requests authentication based on the quantum state of the second entity, the unique operator used to perform the operation at the location of the authentication state, the result of the Bell measurement, and the previously shared authentication key.

8. A quantum entity authentication method performed by a quantum entity authentication apparatus of a first entity, the quantum entity authentication method comprising:

preparing an authentication quantum state that is generated based on an authentication key previously shared with a second entity;

transmitting a quantum state, generated by performing an operation using a prestored unique operator on the authentication quantum state, to a quantum measurement device, and verifying security of a quantum channel by using a result of Bell measurement and the authentication quantum state, the result of the Bell measurement being revealed by the quantum measurement device for the quantum state; and

when the security of the quantum channel is verified, authenticating the second entity using the result of the Bell measurement and the unique operator,

wherein preparing the authentication quantum state is configured to separate the authentication quantum state into a verification state for verifying the security of the quantum channel and an authentication state for authenticating the second entity,

wherein verifying the security of the quantum channel is configured to verify the security of the quantum channel depending on whether a quantum state, generated by performing the operation using the unique operator on the verification state, and a quantum state of the second entity match the result of the Bell measurement,

wherein authenticating the second entity is configured to authenticate the second entity depending on whether a quantum state, generated by performing the operation using the unique operator on the authentication state, and the quantum state of the second entity match the result of the Bell measurement.

9. The quantum entity authentication method of claim 8 , wherein the verification state is configured such that an operation in which a Hadamard operator is included in the unique operator is performed on the verification state.

10. The quantum entity authentication method of claim 8 , wherein verifying the security of the quantum channel is configured such that the quantum measurement device reveals a result of Bell measurement by a detector reacting to an input quantum state, among multiple detectors, using a polarization beam splitter that receives the input quantum state.

11. The quantum entity authentication method of claim 10 , wherein verifying the security of the quantum channel is configured to, when two quantum states are input to the quantum measurement device, decompose the two quantum states into four Bell states and reveal the result of the Bell measurement from which coincidence measurement events in multiple detectors are excluded.

12. The quantum entity authentication method of claim 8 , wherein verifying the security of the quantum channel is configured to receive a location of the verification state from the second entity and transmit information about a unique operator used to perform an operation at the location of the verification state to the second entity.

13. The quantum entity authentication method of claim 12 , wherein authenticating the second entity is configured to receive a location of the authentication state from the second entity and transmit information about the unique operator used to perform an operation at the location of the authentication state to the second entity.

14. The quantum entity authentication method of claim 13 , wherein authenticating the second entity is configured such that the second entity authenticates an additional entity that requests authentication based on the quantum state of the second entity, the unique operator used to perform the operation at the location of the authentication state, the result of the Bell measurement, and the previously shared authentication key.

15. The quantum entity authentication method of claim 14 , wherein authenticating the second entity is configured to, in a case where a basis of the authentication state is a predefined first basis, if the second entity and the additional entity have an identical authentication state and a pair of normal measurement results is derived as the result of the Bell measurement, determine that the additional entity is intervention of an attacker.

16. The quantum entity authentication method of claim 15 , wherein authenticating the second entity is configured to, if the second entity and the additional entity have different authentication states and a coincidence measurement event occurs, compare dark count rates and then authenticate the additional entity.

17. The quantum entity authentication method of claim 14 , wherein authenticating the second entity is configured to, in a case where a basis of the authentication state is a predetermined second basis, separate the result of the Bell measurement depending on whether the second entity and the additional entity have an identical authentication state, and then authenticate the additional entity.