Encryption keys made by the measurement of single light particles – a technology known as quantum key distribution – will resist brute force attacks by quantum computers. (Photo: NUS-CQT)
By Hong Tse Min & Jenny Hogan
Professor Artur Ekert, CQT Director, with Ms Aileen Chia, IMDA’s Deputy Chief Executive (Policy, Regulation & Competition Development) at the MOI signing
Imagine that you need to send some highly confidential data across Singapore. Perhaps you have research and development offices, data centres or critical infrastructure to manage. If you can’t hand-deliver the data yourself or send it through a trusted courier, you might want to use encryption.
Encryption is a technique that can be used to scramble messages so that they can’t be read by unauthorised parties. On the Internet, the HTTPS protocol, for example, is a common encryption method used to help secure customers’ banking or shopping online.
Once a file is encrypted, it is possible to send it over regular communication channels – the internet, for example – with a significantly reduced risk of others being able to decipher it.
There’s growing global interest in an advanced approach to encryption known as quantum key distribution (QKD). For instance, Geneva uses QKD to secure data transfer in elections, while China is seeing large-scale implementation of QKD on a fibre link between Beijing and Shanghai.
It is thus timely that IMDA has signed a Memorandum of Intent (MOI) with the National University of Singapore (NUS) to develop local technical competencies and promote the development of quantum technologies – in particular, QKD, in Singapore. NUS will act through the Centre for Quantum Technologies (CQT), a national Research Centre of Excellence.
Quantum computers will be able to crack some existing encryption methods much faster than current devices.
Keeping ahead of the game
Encryption has always been caught up in an arms race. Just as the Enigma machine used by Germany during the World War II was cracked, progress in technology can threaten modern encryption methods.
Most current encryption methods use mathematically-based techniques that require secret key codes to decipher. The security of such encryption methods depends on the difficulty of the mathematical problem.
This poses a conundrum, with the advent of quantum computing. Quantum computers will be able to solve some mathematical problems much faster than existing computers. This means many of today’s encryption methods – including HTTPS – could be rendered obsolete and cracked nearly instantly in the future.
While quantum technologies with such capabilities might be years away, it is important to keep ahead of the game.
In future, post-quantum cryptography tech might just be used for secured communications on every mobile device.
A more secure solution
Cryptographers are working to develop new mathematically-based encryption techniques that will be resistant to attack by quantum computers. This approach to quantum-safe communication is known as post-quantum cryptography.
QKD is another solution, offering security rooted in the rules of physics. IMDA and CQT will work together to promote the development of this technology.
It makes use of the novel ways that light and matter behave at the particle level to create an encryption key. The key is just a random sequence of ones and zeroes like 1010001101… and so on. The key must be as long as the message written out in binary, then the message is encrypted by adding the key bit by bit along its length.
The only way to decrypt a message that has been encrypted this way is by having the key. The method is known as a one-time pad, named after the encryption paper pads used by spies in the past century. It cannot be reverse-engineered because there is no underlying mathematical problem to solve. That means QKD offers security not only today but also into the future – a feature known as forward security. The method cannot be broken by quantum computers.
Ms Aileen Chia at IMDA's 5G Workshop that was held on the sidelines of Smart Nation Innovations Week.
“In building a more digitalised and connected Singapore, it is important to future-proof our infrastructure and prepare our industry to adopt advanced, even nascent, technologies such as quantum key distribution. The MOI with the Centre for Quantum Technologies at NUS will help to build competencies in Singapore, setting the foundation for Singapore’s quantum key distribution deployment,” said Ms Aileen Chia, IMDA’s Deputy Chief Executive (Policy, Regulation & Competition Development) at the 5G Workshop on 6 June.
The workshop was held on the sidelines of the Smart Nation Innovations Week, at the Conrad Centennial Singapore.
QKD is one possible future-proof approach. A draw-back of the one-time pad was needing a way to get the keys into the hands of the communicating parties without risk of interception. QKD automates this process, and uses light signals sent through fibre or air. The parties use specialised hardware to detect a single light particle at a time, and their measurements generate a symmetric key. This means both parties get an identical key, which they can use to both encrypt and decrypt a message.
The quantum properties of light support the method’s security, replacing the trusted couriers of the past. An unauthorised third party trying to eavesdrop on the key distribution would change the properties of the light particles, introducing discrepancies between the two legitimate parties’ keys.
They can look for this effect by comparing a part of their key, choosing to process the key or discard it entirely if they suspect an eavesdropper. This is done before the encryption step, so there’s no risk of leaking the message.
Quantum-Safe Communications Workshop
Interested in learning more? IMDA and CQT will be hosting an introductory workshop, focusing on quantum-safe technologies for the local industry on 17 July 2018. Additional initiatives such as pilot trials and training programmes will be announced progressively.
You can register for the workshop here.
This story was contributed by Mr Hong Tse Min, Senior Assistant Director, Infocomm Resource & Technology, IMDA; and Ms Jenny Hogan, Associate Director, Outreach and Media Relations, NUS-CQT.