In a new study, scientists proposed a conceptual design of "quantum blockchain", which may protect the blockchain system from quantum computer hackers. The new coding program can be interpreted as non classically influencing the past; Therefore, this decentralized quantum blockchain can be regarded as a quantum networked time machine.

Blockchain is a classic database type, which stores information related to the past, such as financial or other transaction history. The unique design makes it difficult to tamper with, and does not require a central agency to maintain its continuous accuracy. The most famous application of blockchain is known as Bitcoin. However, in recent years, various startups, enterprise alliances and research projects have explored many other potential uses of blockchain technology.

According to the 2015 World Economic Forum survey, it is estimated that by 2027, 10% of global GDP will be stored in blockchain technology.

However, blockchain may face trouble due to another major technology coming soon - quantum computer. The traditional computer represents the data as 1 and 0 by controlling the transistor on or off, while the quantum computer uses quantum bits. Due to some surreal characteristics of quantum physics, quantum bits can be in the superposition state of 0 and 1 at the same time.

Now scientists have developed a quantum technology to ensure the security of each blockchain. In other words, this new blockchain encryption method uses exactly the quantum computing technology that poses a security threat to the blockchain itself.

Evgeny Kiktenko, a researcher of Quantum Research Center, and his team have designed, built and tested the first quantum blockchain system. As the name implies, the system will ensure the security of the blockchain with quantum encryption technology. At present, this technology has been put into commercial application.

The quantum identification system built by Evgeny Kiktenko team is based on solid and reliable physical laws to solve the consensus mechanism problem, which can ensure that each party involved can safely and accurately authenticate the other party. At the same time, because everyone's "quantum information" is associated with all transactions, the information becomes relatively open, and it is not easy to tamper with it.

Evgeny Kiktenko said that they had built a quantum identification system described above using the commercial quantum encryption system of the Swiss company ID Quantique. They said: "We have developed a blockchain protocol based on information theory security authentication. In this network, each pair of nodes are connected through a quantum key distribution link."

In order to verify the feasibility of the quantum blockchain technology, the team has tested it in a network with four users, and one of the users tried to verify the reliability of the system by making double expenditures. "This agreement only identified and cancelled the transaction application with double expenditure through two rounds of information communication, and formed a block that only allowed legal transactions at the same time."

In any case, the development of quantum technology is like this. A mature quantum computer can not only capture any information saved using traditional cryptography, but also be used to combine with blockchain technology to improve the security level of password protection. It has to be said that technology is progressing bit by bit in such self contradiction.