Quantum Computers are coming.

Prepare now for quantum computers, QKD and post-quantum encryption
The predicted processing power of quantum computers is likely to make existing encryption algorithms obsolete. Quantum key distribution (QKD) is a possible solution – we investigate whether QKD is viable
Quantum computers have been on the horizon for several years, but recent breakthroughs mean we could expect to see enterprise-level quantum computers within 20 years.

Quantum computers use the principles of quantum mechanics, such as superposition and entanglement, to perform their processes. While current computers use binary digits (bits), quantum computers use quantum bits (qubits), which can be in superpositions of states. This allows quantum computers to perform multiple calculations simultaneously, making them exponentially faster.

Given their ability to perform multiple processes simultaneously, quantum computers will enable many useful applications, such as imaging technologies and the modelling of chemical reactions. But these are just two areas in which quantum computers are expected to have a huge impact.

Quantum computers are still very much at the experimental stage, mostly under the remit of private research and development laboratories. However, it is only a matter of time before the engineering hurdles are overcome and quantum computers become cost-effective.

Attempting to prophesise when technology will become available is always risky. That said, many professionals believe the 20-year time-frame is realistic, but quantum computers are likely to become available to governments, universities and research institutes a bit sooner.

Encryption in the quantum age of computers

Quantum computers will have grave consequences for current encryption algorithms. “In the world of counting on being able to hide the key through prime numbers, when quantum comes online, all of a sudden that does not work so well,” says Jeff Hudson, CEO of Venafi. “Quantum computers can theoretically instantaneously work what would take a long time for standard computers.”

The current encryption protocols are based on complex mathematical problems. These mathematical problems are so complicated that it would take many years for conventional computers to solve them without the encryption key. “The flaw at the moment is that the message and the private key travel together, so if you have enough processing power you can work out the key and compromise the data,” says Colin Tankard, managing director of Digital Pathways. “That is where quantum computing is going to break encryption, because it will be able to process it really quickly.”

It is believed that a sufficiently powerful quantum computer running Shor’s algorithm could easily break these encryptions in a fraction of the time a conventional computer would take. “For a normal computer it is still around 70 years before they can break AES256 encryption,” says Tankard. “The faster the processor, the quicker that is going to be.”

Read the full article in Computer Weekly here