14 DAY TRIAL // For several years, numerous experts and officials have been advocating for the advantages of introducing quantum money in public circulation. It has several advantages over existing electronic currencies, mostly because it cannot be counterfeited, abused or forged. But there are also a number of difficulties associated with using it, such as measuring its value, and protecting it from the hands of quantum thieves. Here are some of the problems that need to be resolved before quantum currency can become a reality.
For starters, quantum money would only be available online, without the need to involve banks and credit card companies. But purchasing items using such a type of currency would be entirely anonymous, which does not sit well with authorities. At this point, all transactions leave behind an electronic paper trail, which can be untangled in the event of an investigation. Quantum money would make this impossible. Even then, the question of authenticity raises its head immediately.
Like checking banks accounts, people need to be able to certify the authenticity of their money at any time. But quantum states are generally destroyed when measured, which means that physicists need to find new ways of doing this. In other words, at this point, checking for the properties of quantum money would be the same as burning a $100 bill, to see whether it burns. Public-key encryption would be a solution, but this raises the necessity of devising complex mathematical calculations. Experts would need to devise equations that are easily achievable in one direction, but impossible in the opposite one.
In addition to all of this, the Internet, which is supposed to be the network through which this new money is distributed and verified, is not yet capable of carrying quantum states. It will be at least two decades, experts believe, until the infrastructure supporting the World Wide Web becomes advanced enough for quantum currency to be introduced. Even then, due to the unstable nature of quantum states, small sums of money would disappear out of banks accounts into thin air, just because some of the deposit has been accessed. Few people will accept this, let alone banks, Technology Review reports.