Quantum tokens
View Patent ↗Secure, semi-classical authentication schemes are presented. An authentication token is generated by applying a pre-determined measurement to a plurality of random quantum states to obtain a sequence of classical measurement outcomes. The token is validated by receiving the classical measurement outcomes and verifying whether the sequence corresponds to a statistically plausible result for the pre-determined measurement of the plurality of quantum states.
1. An agency system comprising:
a first agent quantum device that generates, at a first space-time point, a plurality of random quantum states, each of the plurality of random quantum states chosen from a set of non-orthogonal quantum states; and
a second agent measurement apparatus at a second space-time point, wherein the second agent measurement apparatus applies a pre-determined measurement associated with the second space-time point to the plurality of random quantum states to generate measurement outcomes and determine whether the measurement outcomes correspond to a statistically plausible result for the pre-determined measurement;
wherein the pre-determined measurement generates a valid token in the second space-time point.
2. The system of claim 1 , wherein the plurality of random quantum states are chosen independently randomly from among pure states of a plurality of possible bases for a quantum state space.
3. The system of claim 2 , wherein the quantum state space is a two-dimensional qubit space and the plurality of random quantum states represent quantum bits (qubits).
4. The system of claim 3 , wherein each of the plurality of random quantum states comprises BB84 states for the two-dimensional qubit space.
5. The system of claim 3 , wherein each of the qubits is encoded in a photon of electromagnetic energy.
6. The system of claim 5 , wherein each qubit is encoded as a polarization state of the photon.
7. The system of claim 6 , wherein each qubit is represented by the polarization state of a weak light pulse with a low expected photon number.
8. The system of claim 2 , wherein the pre-determined measurement comprises a projection of each of the plurality of random quantum states onto one of the pure states of a corresponding quantum state space.
9. The system of claim 1 , wherein the plurality of random quantum states represent quantum bits (qubits).
10. The system of claim 1 , wherein the plurality of random quantum states are entangled.
11. The system of claim 1 , wherein the valid token comprises only measurement results corresponding to quantum states of the plurality of random quantum states that are successfully measured.