Imagine waking up to discover your bank account drained, and emails and private messages no longer secure.

That could be reality when powerful quantum computers are finally capable of breaking the encryption that protects the banks, government agencies and militaries around the world.

That date is known as “Q-Day”, and it could come sooner than many expect.

When built at large-scale, a quantum computer will one day be able to come up with solutions to incredibly complex problems in minutes, compared to years.

Former criminal-hacker-turned-cyber-security-expert Bastien Treptel predicts viable quantum computing will exist in five years.

Treptel once hacked the Commonwealth Bank, but now works with the big banks to protect them from being susceptible to an attack. He said a quantum computer could theoretically crack encryption almost instantaneously.

The technology can also be used for good, and 10 News+ has met the scientists building a quantum computer inside the University of Sydney.

Associate Professor John Bartholomew said “it’s going to benefit society”, unlocking major breakthroughs such as designing new medicines and more efficient cars and planes, as well as for financial market modelling.

Both experts believe Q-Day can be avoided and urge businesses and governments to update encryption methods now, to help ensure the benefits of quantum computing far outweigh the risks.

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