Quantum Communications Hub - Enabling a quantum-safe future
Major advances in quantum computing will no doubt make a huge and positive difference to the world we live in, from advancing drug development, to reducing environmental impact by optimising energy networks, calculating extremely efficient transport routes, and developing cleaner industrial processes, for example. However, large scale quantum computers also pose severe threat to the world’s communications systems as they will render current cybersecurity methods, underpinned by cryptography, vulnerable to hacking attacks.
How are communications secured currently and what is the threat?
Current cybersecurity relies upon conventional cryptography, this comes in two forms: symmetric and asymmetric. Both forms of conventional cryptography utilise mathematical algorithms and require the sharing of cryptographic keys. In symmetric cryptography, senders and receivers use the same key (which is secret and known only to them) to encrypt and decrypt secure communications; while in asymmetric cryptography, two keys are used: a public key (which is not secret) to encrypt data, and a private key (known only by the receiver) to decrypt it. A combination of both forms of cryptography is used to secure communications today. First, asymmetric cryptography is used to establish a shared secret key; this secret key is then used to secure communications through symmetric cryptography. At the minute, it is virtually impossible to work out a secret key if only the public key is known. However, this will change when large quantum computers able to execute an algorithm (devised by Peter Shor) are available, and thus communications will be hackable.
Furthermore, although quantum computers large enough to hack current methods of cryptography do not exist yet, communications are at risk from retrospective decryption and so those requiring long-term security should be protected now. Information which is encrypted with current cryptographic techniques could be intercepted, stored and then decrypted once large quantum computers arrive, meaning the development and deployment of communications that are “quantum-safe”– that is safe in a future world where all forms of quantum technology exist, including large quantum computers – is crucial and required urgently.
Delivering quantum-safe solutions
Two major advances are being made to counter the threat posed by quantum computers and provide a quantum-safe solution.
Firstly, Quantum Key Distribution (QKD) technologies are being developed. QKD is a mature quantum technology which enables the generation of symmetric keys to take place using quantum signals – these are guaranteed secure by the laws of quantum physics. QKD does require users to have an initial shared secret key for authentication. However, as long as this is the case, an unlimited amount of new key data can be generated and be guaranteed secure.
Secondly, quantum-resistant or post-quantum cryptography (PQC) is being developed. This new type of cryptography utilises new mathematical encryption techniques which are immune to attack by Shor’s algorithm and are expected to be immune to other algorithms that could be developed in the future.
To provide a complete quantum-safe solution for cybersecurity, QKD and PQC should be deployed simultaneously. QKD should be used to create secret keys, authenticated with asymmetric PQC. This would mean that new quantum keys will remain secure, even if the PQC was ever to be broken by new algorithms, because the quantum keys have no relationship to the authentication data. This means any transactions or communications reliant on the keys would remain secure indefinitely.
The Quantum Communications Hub, funded through the UK National Quantum Technologies Programme, is working to develop and commercialise a variety of QKD technologies, enabling quantum secure communications to take place at all distance scales. It is also working to develop asymmetric PQC and its hardware implementations. Alongside this, the Hub is working on progressing hybrid systems which integrate PCQ with QKD, to future-proof cybersecurity.
To find out more about the Quantum Communications Hub’s work to deliver quantum secured communications at all distance scales, visit the Hub website or download our leaflet on quantum-safe secure communications.
Laura Foster
Laura is techUK’s Associate Director for Technology and Innovation.
