Quantum Key Distribution With Deterministic Basis Selection
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Solution Overview
Problem
Existing quantum key distribution (QKD) methods, such as the BB84-QKD protocol, utilize only about 50% of the theoretically attainable data key rate due to random selection of quantum bases, leading to discarded measured quantum states and inefficiencies.
Innovation Solution
A QKD method that determines a first common secret key using computationally secure techniques, allowing nodes to unambiguously determine a series of quantum base states, ensuring both nodes use the same states for encoding and decoding, thereby enhancing the data key rate by utilizing all transmitted quantum states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If random quantum basis selection is used (BB84-QKD protocol), then security is maintained, but data key rate is reduced to about 50% of theoretical maximum
Solution Approach 1:
The patent applies preliminary action by pre-determining the quantum basis states through a computationally secure key exchange protocol before the actual quantum key distribution. This allows both parties to know which bases to use in advance, eliminating the need for random basis selection and subsequent discarding of mismatched measurements, thereby achieving 100% utilization of transmitted quantum states while maintaining security through the preliminary key exchange
Solution Approach 2:
The patent changes the parameter of basis selection from random to deterministic based on a pre-shared secret key. By transforming the basis selection mechanism from probabilistic (random) to deterministic (based on pre-agreed key), the system eliminates waste while maintaining the security properties required for QKD operation
2Productivity
If all transmitted quantum states are utilized, then data key rate is enhanced, but requires deterministic quantum basis states
Solution Approach 1:
The patent introduces an intermediary element - a computationally secure key exchange protocol - that mediates between the requirement for deterministic basis states and the need for security. This intermediary key exchange mechanism enables both parties to derive identical quantum basis states without direct communication about the bases themselves, thus utilizing all quantum states while managing complexity through a standardized key exchange process
Data Source
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AI summary
A quantum key distribution (QKD) method for distributing quantum keys across at least one communication channel (18, 20) of a communication network (12) is described. The at least one communication channel (18, 20) connects at least two nodes (14, 16) of the communication network (12), wherein the at least two nodes comprise a first node (14) and a second node (16). The QKD method comprises the following steps: - determining, by means of the at least two nodes (14, 16), a common secret key, wherein the common secret key is a data key; and - determining, by means of each of the at least two nodes (14, 16), a series of quantum base states based on the common secret key, wherein the series of quantum base states corresponds to a common secret quantum key. Further, a communication method and a communication system (10) are described.