By Dr. Jonathan Jogenfors, Quantum Bitcoin Inventor, Hacker, Atea Senior Information Security Consultant, CSA Blockchain Cybersecurity and Privacy Best Practices Group Advisor
Money requires copy protection. If banknotes or coins could be forged, they would hardly be usable in daily life. Blockchain technology has been proposed as a new way of preventing double-spending in digital currencies because they have advantages over traditional centralized systems, i.e. decentralization brings resilience and greater anonymity. But, a radically different approach can be made using quantum mechanics.
In effect, a surprising consequence of quantum theory is the no-cloning theorem (https://doi.org/10.1038%2F299802a0) which forbids arbitrary copying of quantum states; this is essentially nature’s own copy protection. Here, we do not have to rely on microprint and watermarks. Instead, forgery is prevented by simply applying the laws of physics! In such “quantum money” systems, a bank mints units of currency that each contain a collection of quantum states so that regular users can verify if these units are valid.
Can we make a Quantum Money system using a Blockchain?
The answer is yes! This can be accomplished through the use of Quantum Bitcoin (https://ieeexplore.ieee.org/abstract/document/8751473) where these two techniques are combined. In the paper, Quantum Bitcoin is described as sharing advantages with both Bitcoin and Quantum Money systems. Basically, forgery is prevented by the no-cloning theorem, there is no limit on transaction scalability, and mining is performed using a two-step process. However, quantum money presently exists as a theoretical concept. Current technology does not yet allow us to reliably create, store and process quantum states with high enough fidelity for practical use. Additionally, while classical bitcoin can be easily transferred over the internet, a quantum bitcoin would need to be transferred physically or by using a “Quantum Internet” (https://www.energy.gov/articles/quantum-internet-future-here).
Quantum technology is an interesting frontier in physics with many new tangible applications just around the corner. In addition to the much-hyped quantum computer, quantum money is another example that could have disruptive effects on our society worldwide. While the current state of art is far from being practical, it is worthwhile to envision what is possible once advanced technologies mature.
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