The evolution of blockchains is proceeding faster. Since the beginning of Bitcoin, we have witnessed four main ways to protect blockchain networks – from processors to special-purpose chips ASIC. Each method raised the bar for competition among miners and significantly increased the complexity of calculations.
Currently, the attention of the crypto community is focused on Bitmain ASIC chips and their threat to the security and cost of cryptocurrencies – in particular, the broadcast (ETH / USD) and bitcoin (Bitcoin). However, a more serious threat to quantum computers is already looming on the horizon.
Given that a quantum computer is about 17 billion times more powerful than usual, some cryptocurrency projects already claim that their systems are resistant to quantum computing (an example is the Tangle IOTA network).
Del Rajan and Professor Matt Visser, researchers from the University of Victoria, New Zealand, write in their work “Quantum blockchain based on entanglement in time” (Quantum Blockchain using entanglement in time)
“A more appropriate solution would be the initial quantum blockchain, built from quantum information. Its design will be fully integrated into the quantum network. ”
The novelty of their ideas compared to what IOTA offers is to be tangled in time or, in the words of the authors, “such a blockchain can be considered as a quantum network time machine”.
Rajan and Visser believe that the stability of any classic blockchain before a quantum attack “is in doubt, given the enormous forces applied to the search for new quantum algorithms that can potentially undermine all the efforts of cryptocurrency developers.”
Quantum projects for a long time remained the domain of superpowers. Their opposition in this area was even dubbed the “new arms race”. The Chinese government is going to spend $ 10 billion to create the National Laboratory of Quantum Information Sciences in Hefei, and this is only part of the PRC budget for quantum projects. Its construction is scheduled for completion in 2020. China is also known for its activity in cyberspace – according to Foreign Policy magazine, the number of Chinese cyber war is 50-100 thousand people.
The European Commission recently allocated 1 billion euros for quantum research. Although the United States has somewhat reduced its expenses, they spend about $ 200 million on research in this area.
The solution of a problem that a conventional supercomputer will take dozens of years to complete will take a few days for a quantum one. As in space and nuclear races, the first country to master quantum computing will determine the future development of the world for many years and bring state control and espionage to a new level.
Quantum computers can break into cryptographic protocols that are used to protect classic blockchains and serve as the basis for the security of the modern digital world.
The information is stored as zeros and ones in conventional computers. Quantum computers work with quantum bits – qubits. They can not be copied and they are a superposition of zeros and ones (that is, they can be both zero and one at the same time, allowing you to perform calculations in parallel).
The fundamental difference between quantum cryptography is that qubits, unlike ordinary bits, can not be copied. Any attempt to save data in the classical sense will destroy the superposition underlying the incredible computing power of a quantum computer — power capable of undermining the cryptography of classic blockchains by falsifying data in previous blocks without changing the hash results.
Rajan and Visser believe that “entanglement in time, as opposed to entanglement in space, plays a key role in the advantage of quantum blockchains over ordinary ones”.
The most important aspect of strong quantum cryptography is quantum key distribution (CRK), when the sender uses a cryptographic key encoded into a quantum signal to encrypt the message. If someone tries to intercept the key, he will be destroyed.
Technology giants such as IBM, Google and Microsoft are also actively fighting for “quantum supremacy.” One day it will drastically change the business. IBM introduced the world’s first quantum computer of 50 qubits last November. Although it can simulate molecules and conduct chemical experiments, IBM vice president of research, Jeffrey Welser, said that it is unknown when “quantum computers will be used for everyday applications that everyone can understand.”
Google solemnly introduced the 72-qubit Bristlecone quantum chip in March. The head of the project, John Martinis, promised to achieve quantum supremacy by the end of the year. By copying the confrontation of the two superpowers, China’s largest retailer Alibaba, which also seeks to dominate this sphere, cooled Google’s ambitions by conducting its own chip analysis. It turned out that his error rate is too high.
Practical or commercial use of quantum computers is still far away. The first company to make a breakthrough will be able to rent or sell their cars to other companies that want to enter the market. For example, Daimler and JP Morgan can use quantum computers to increase battery life and optimize financial models.
Currently, the main problem remains the lack of infrastructure necessary to create a quantum blockchain – a global quantum network connecting devices with fiber lines and satellite channels. Ultimately, it will become the founder of the quantum Internet. Although Rajan and Visser admit that they are still far from the actual implementation, they argue that “the individual components of this system have already been created and their efficiency has been experimentally confirmed.”
Quantum cryptography is the most developed of all branches of quantum physics. Projects, even more ambitious than the “Internet of things” may soon appear, considering the progress in the development of blockchains.