Scientists in China have developed a new method for quantum key distribution (QKD) that can increase the speed of intercity quantum networks. These networks are highly secure against hacking, with data being encrypted and decryption keys being transmitted through quantum mechanics. However, existing QKD methods have a limited range and can be difficult to implement. The new method shows promise in overcoming these limitations.
The new method, known as mode-pairing quantum key distribution (MP-QKD), was first introduced by a research team headed by Dr. Ma Xiongmeng at Tsinghua University in 2022. It eliminates the need for a complex step called "phase locking". The team collaborated with another team led by renowned quantum communication expert Professor Pan Jianwei to put the method into practice, and the results were impressive. The study was published in the journal Physical Review Letters.
Quadratic Improvement
According to the paper, the researchers stated that MP-QKD can offer a "quadratic improvement" in the key rate, or the speed of QKD, compared to traditional measurement-device-independent QKD (MDI-QKD) when utilized in metropolitan and intercity networks. Additionally, the new method performs even faster over longer distances of 300 to 400 kilometers, with a three-order-of-magnitude increase in speed, as reported by Phys.
The paper also mentioned that MP-QKD can be accomplished using readily available "off-the-shelf" lasers, making it a practical technology that is ready for implementation. The scientists anticipate that this new technology will be widely adopted in future intercity quantum networks. Quantum key distribution (QKD) is a method of transmitting secure keys for the encryption and decryption of data over a communication network.
Unlike classical encryption methods, the security of QKD is based on the fundamental laws of physics and the properties of quantum mechanics. In QKD, a secret key is generated and transmitted using individual particles of light, or qubits, which can be transmitted over optical fibers or through free space. The key is used to encrypt and decrypt the data being transmitted, ensuring that it cannot be intercepted or eavesdropped on without being detected. This makes QKD a highly secure method of transmitting sensitive information.
How QKD Works?
QKD works by transmitting a sequence of qubits, or individual particles of light, between two parties, usually referred to as Alice and Bob. The qubits are transmitted in such a way that any attempt to intercept or eavesdrop on the transmission will inevitably alter the state of the qubits, making it possible for Alice and Bob to detect the presence of an eavesdropper.
Once the transmission is complete, Alice and Bob use the qubits to generate a secret key that is used to encrypt and decrypt the data they wish to transmit. The key is generated by performing measurements on the received qubits and publicly communicating the results. Any attempt to intercept the qubits will cause a detectable disturbance in the qubits, making it possible for Alice and Bob to know that their communication has been compromised and discard the key.
In this way, QKD provides a highly secure method for transmitting sensitive information over a communication network. The security of QKD is based on the principles of quantum mechanics and the laws of physics, making it essentially hacker-proof. This makes QKD an attractive solution for organizations and governments that need to transmit highly sensitive information securely.
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