Currently, quantum computers are not stable enough to perform complex operations for an extended period of time. The most powerful quantum computer to date, IBM's Osprey, has 433 quantum bits (qubits), while computer scientists estimate that it would take 1 million qubits to fully realize the technology's potential.
However, in 1994, mathematician Peter Shor developed an algorithm that, theoretically, could be used on a powerful quantum computer to crack the RSA encryption protocol commonly used in online transactions.
Recently, a research paper suggested a hybrid classical-quantum computing approach could bring quantum computing forward. Countries, corporations, and venture capitalists are in a race to develop the first robust quantum computer as they can be used to both crack encryption and secure communications in a quantum world. Investment has been significant in order to commercialize the technology.
To understand the answer, first you need to understand how a classical computer functions.
The basic unit of classical computing is a bit. It can sit in one of two binary states: off or on, often described as 0 or 1.
A sequence of eight bits is known as a “byte”, which can store much more data than a bit.
While each individual bit contains just two values, a full byte has 256 unique combinations.
In a quantum computer, our bits are replaced with quantum bits, or qubits. These exist in what’s called a quantum state, where until they are measured they can be considered both “on” and “off” at the same time.
If our bits were coins, think of qubits as those same coins but mid-coin flip. At some point they will land on heads or tails but, while in the air, they have some probability of being one or the other. In quantum computing, this “mid-coin flip” state is called “superposition”.
A classic computer will check a problem in sequence, one at a time. But a quantum computer can arrange qubits in ways that maximise the possibility of finding the correct outcome. The maths behind these arrangements is referred to as “quantum algorithms”, and they are the complicated magic at the heart of quantum computing.
The normally time-consuming task of finding every possible outcome to a problem is no longer a problem on a quantum machine — and given all of them, checking which is shortest is relatively easy with the right algorithm.
Today's quantum computers face several obstacles that need to be addressed before they can reliably solve problems that classical computers cannot.
The biggest challenge is the instability of qubits, which are made of delicate subatomic particles in delicate quantum states that are easily disrupted. Any interaction with the environment, such as heat, electronic signals, magnetic fields, and cosmic rays, can impact the qubits' state, making it difficult to measure the correct answer. This "outside noise" masks what is happening in the quantum machine, resulting in the loss of refinement.
Although some interaction with the environment is necessary, it creates reliability issues. That's why most prototype quantum computers operate in a cryogenic chamber just above absolute zero, which is colder than deep space. This keeps the qubits stable for long enough to be usable.
And remember, just a small reliability issue can completely change the value of a full byte or introduce errors into a system.
Quantum technologies available today can already be used to optimize logistics or monitor brain activity in hospital patients. However, the real potential will be unlocked with the development of robust and error-free quantum computers. The competition to develop this technology is driven by both commercial interests and geopolitical rivalry, with tech giants such as Google, IBM, and Microsoft investing heavily, as well as numerous start-ups.
Apart from the economic possibilities, governments are concerned about the security implications of developing quantum computers. The most common method used to secure all our digital data relies on the RSA algorithm, which is vulnerable to being cracked by a quantum machine.
However, quantum technology might also help us invent new materials and drugs, develop smarter financial trading strategies, and create secure new methods of communication. The potential applications of quantum computing open up entirely new areas of technology and unlock solutions that we could not have achieved in the past.
The current quantum computers we have are not good enough to run complex algorithm to crack RSA passwords. We need to make big improvements before we can build quantum computers with enough qubits to solve complex problems. Some estimate it may take between 20 to 40 years, and others claim we are years, not decades away from this level of innovation.
For several years, the US government has been planning for a quantum world and has been running competitions to find the most secure communication protocols of the future that would forestall the threat of Q-day. The US National Institute of Standards and Technology is in the process of approving new cryptography systems — based on problems other than factorisation — that are secure against both quantum and classical computers. It’s a race between quantum computers and the fix — which is to stop using RSA.
But whatever new security protocols are finally approved, it will take years for governments, banks and internet companies to implement them. That is why many security experts argue every company with sensitive data should be preparing for Q-day today.
Even if private sector investment slows, the escalating geopolitical rivalry between the US and China will provide added impetus to develop the world’s first robust quantum computer. Neither Washington nor Beijing wants to come second in that particular race.
SOURCE - Financial times