Its hard to forge what you cant observe
Equinox Graphics/Getty Images
By Matt Reynolds
A quantum upgrade could make old-fashioned cheques the most secure way to send money. Researchers have proven that quantum computers could in theory create and cash cheques that are nearly impossible to forge.
Quantum computers store information using qubits which, unlike the ones and zeros of classical computing, can exist in two states simultaneously. This is known as quantum superposition.
But its impossible to observe a qubit while its in a superposition it collapses into either a one or zero as soon as you measure it. This is what makes quantum cheques so secure. If anyone intercepted a cheque and had a peek inside, they would only be able to see the qubit in its collapsed state.
The idea of quantum currency has been kicking around for decades, but until last year, very few computer scientists had access to quantum computers to test their theories. Now, researchers using IBMs cloud-based quantum computer have run the numbers.
Although this study is only a proof of concept, quantum technology hasnt got far to go until these systems are workable says Prasanta Panigrahi, who led the study at the Indian Institute of Science, Education and Research in Kolkata. Even existing five-qubit quantum computers like the one used in this experiment could eventually be used to issue and verify quantum cheques, he says. But for now, these kinds of transactions cant be scaled to a wide population and they arent exactly the most convenient way of moving cash.
Say Alice wants to pay Bob using a quantum cheque. She would have to go to the bank, verify her identity and then the bank would issue her with two qubits taken from its central quantum computer. These qubits are inextricably linked to the remaining qubits within the banks central computer a quality known as quantum entanglement. Measuring the state of any one qubit in an entangled system will reveal the state of all qubits within that system. The bank can use this entanglement to verify that its coffers were the origin of a quantum cheque.
Alice can then take her qubits and encode one of them with the amount of money she wants to give to Bob. She then gives this qubit to Bob and he takes it to the bank to cash. The bank verifies that its definitely a qubit from its own system, and that it has been encoded by Alice, and cashes the cheque.
Although you cant forge a quantum cheque, there is one weak point in this system, says Subhayan Roy Moulick, a researcher at the University of Oxford who originally proposed the experimental proof. To encode her qubit, Alice has to access it using a passcode, so if someone stole that passcode and her qubit, they could theoretically tamper with the qubit. But as long as the passcode is memorised or securely locked away the risk of tampering is extremely low, says Moulick.
Then theres the problem of transporting qubits. Some of our current quantum computers need huge cooling systems. It is possible to store qubits at room temperature by using diamonds, but Moulick says that a quantum cheque is more likely to be a laptop-sized black box than something you can slip into your pocket.
Scott Aaronson at the University of Texas suggests applying the concept in a slightly different way. If the bank managed the entire transaction, he says, it would still be ultra secure, but there would be no need for anyone to carry around quantum cheques.
However, the real application is a way off, Aaronson says. At the moment, the qubits in the IBM system only last for microseconds at a time. Ideally, Aaronson says, one would like cheques that can last longer than that before being cashed or deposited.
Besides, in this experimental scenario, the bank gives away two qubits every time it issues a cheque. Even if the bank only issued one cheque a day, it would need hundreds of qubits, and quantum computers of that size are still decades away from becoming reality. The current most powerful quantum computers only have 20 qubits, although Google is on track to build a 49-qubit machine by the end of this year.
Erika Andersson at Heriot-Watt University in Edinburgh, UK, thinks that the whole idea is unnecessarily complicated. Instead, quantum computers could be put to better use creating secure keys instead of physical cheques, she says. The bank could authenticate transactions using a technique called quantum key generation, where quantum computers are used to generate shared security keys to verify the identity of the parties involved in the transaction. This would cut out the need for anyone to carry qubits around.
And, unlike qubit cheques, quantum keys are already catching on in the real world. The technology was used to help keep the results of the 2007 Swiss election secure while in 2012 the Chinese government used it to help keep the discussions at the 2012 National Congress away from prying eyes.
Read more: Google on track for quantum computer breakthrough by end of 2017
More on these topics:
- What is quantum computing? - Definition from WhatIs.com - February 5th, 2018
- The Era of Quantum Computing Is Here. Outlook: Cloudy ... - January 26th, 2018
- IBM puts its quantum computer to work in relaxing, nerdy ASMR ... - January 8th, 2018
- Quantum computing is going to change the world. Here's what ... - January 8th, 2018
- Is Quantum Computing an Existential Threat to Blockchain ... - December 25th, 2017
- What is Quantum Computing? | SAP News Center - December 23rd, 2017
- Quantum Computing Explained | What is Quantum Computing? - December 21st, 2017
- New silicon structure opens the gate to quantum computers - December 14th, 2017
- Microsoft offers developers a preview of its quantum ... - December 12th, 2017
- Quantum Computing Is the Next Big Security Risk | WIRED - December 8th, 2017
- Yale Professors Race Google and IBM to the First Quantum ... - November 16th, 2017
- IBM's processor pushes quantum computing ... - engadget.com - November 16th, 2017
- Quantum computing - news.microsoft.com - November 1st, 2017
- Intel Takes First Steps To Universal Quantum Computing - October 13th, 2017
- Qudits: The Real Future of Quantum Computing? - IEEE Spectrum - October 13th, 2017
- quantum computing - engadget.com - October 13th, 2017
- Quantum Computing | Intel Newsroom - October 13th, 2017
- What will you actually use quantum computing for? | ZDNet - October 11th, 2017
- Here's what quantum computing is and why it matters - October 6th, 2017
- Microsoft just upped its multi-million bet on quantum computing - ZDNet - September 7th, 2017
- Microsoft's Aussie quantum computing lab set to scale up next-gen ... - ARNnet - September 7th, 2017
- An Entirely New Type of Quantum Computing Has Just Been Invented - Futurism - September 7th, 2017
- Quantum computing event explores the implications for business - Cambridge Network - August 30th, 2017
- Quantum Computing Is Coming at Us Fast, So Here's Everything You Need to Know - ScienceAlert - August 27th, 2017
- How quantum mechanics can change computing - San Francisco ... - San Francisco Chronicle - August 25th, 2017
- Commonwealth Bank investing in Australia's first quantum computer company - Which-50 (blog) - August 25th, 2017
- How quantum mechanics can change computing - The Conversation US - August 23rd, 2017
- Introducing Australia's first quantum computing hardware company - Computerworld Australia - August 23rd, 2017
- IEEE Approves Standards Project for Quantum Computing ... - insideHPC - August 23rd, 2017
- $495.3 Million Quantum Computing Market 2017 by Revenue Source, Application, Industry, and Geography - Global ... - PR Newswire (press release) - August 18th, 2017
- Physicists Have Made Exotic Quantum States From Light - Futurism - August 16th, 2017
- Machine learning tackles quantum error correction - Phys.Org - August 15th, 2017
- Quantum Internet Is 13 Years Away. Wait, What's Quantum Internet? - WIRED - August 15th, 2017
- Blind quantum computing for everyone - Phys.org - Phys.Org - August 12th, 2017
- Quantum Computing Is Real, and D-Wave Just Open ... - WIRED - August 12th, 2017
- Quantum Computing Market Worth 495.3 Million USD by 2023 | 08 ... - Markets Insider - August 10th, 2017
- China uses a quantum satellite to transmit potentially unhackable data - CNBC - August 10th, 2017
- Physicists Take Big Step Towards Quantum Computing and ... - Universe Today - August 1st, 2017
- Why you might trust a quantum computer with secretseven over ... - Phys.Org - July 12th, 2017
- Quantum-computer node uses two different ion species - physicsworld.com - July 10th, 2017
- Quantum Computers vs Bitcoin How Worried Should We Be? - The Merkle - July 10th, 2017
- Technique for measuring and controlling electron state is a ... - UCLA Newsroom - July 9th, 2017
- Quantum Computers Made Even More Powerful with New microchip generating 'Qudits' - TrendinTech - July 8th, 2017
- Quantum Computing Record Broken - Wall Street Pit - July 8th, 2017
- Alkermes and IBM's quantum computing. Who'll be the big winner? Malcolm Berko - Durham Herald Sun - July 6th, 2017
- Qudits: The Real Future of Quantum Computing? - IEEE Spectrum - IEEE Spectrum - July 1st, 2017
- Google to Achieve "Supremacy" in Quantum Computing by the End of 2017 - Big Think - July 1st, 2017
- Quantum Computing Becomes More Accessible - Scientific American - July 1st, 2017
- Tektronix AWG Pulls Test into Era of Quantum Computing - Electronic Design - June 2nd, 2017
- Toward mass-producible quantum computers | MIT News - MIT News - June 2nd, 2017
- Purdue, Microsoft Partner On Quantum Computing Research | WBAA - WBAA - June 2nd, 2017
- IBM boosts power of quantum computing processors as it lays ... - www.computing.co.uk - May 22nd, 2017
- IBM makes leap in quantum computing power - ITworld - May 22nd, 2017
- The Bizarre Quantum Test That Could Keep Your Data Secure - WIRED - May 18th, 2017
- Molecular magnets closer to application in quantum computing - Next Big Future - May 15th, 2017
- Inside Microsoft's 'soup to nuts' quantum computing ramp-up - Computerworld Australia - April 29th, 2017
- Quantum computing is about to disrupt the government contracts market - Bloomberg Government (blog) - April 22nd, 2017
- Scientists: We Have Detected the Existence of a Fundamentally New State of Matter - Futurism - April 22nd, 2017
- What Sorts Of Problems Are Quantum Computers Good For? - Forbes - April 22nd, 2017
- quantum computing - WIRED UK - April 22nd, 2017
- What is Quantum Computing? Webopedia Definition - March 18th, 2017
- Here Is Everything You Need to Know About Quantum Computers - Interesting Engineering - March 18th, 2017
- Quantum Computing Market Forecast 2017-2022 | Market ... - March 18th, 2017
- Mathematician breaks down how to defend against quantum ... - Phys.Org - February 28th, 2017