Threats to current cryptographic techniques created by major advances in quantum computing are widely acknowledged as both real and forthcoming. Although quantum computers large enough to undertake hacking do not yet exist, retrospective decryption is a very real threat and critical data requiring long-term security should be protected now. Information which is encrypted with current cryptographic techniques can be intercepted, stored and decrypted once large quantum computers arrive. There is a clear and urgent need to make all aspects of cyber security “quantum-safe” – that is safe in a future world where all forms of quantum technology exist, including large quantum computers. Quantum Communications Hub researchers are working to address this need.
Two major advances are being developed to counter this threat and to progress cyber security to being quantum-safe.
(1) Quantum key distribution (QKD) enables the communicating parties to generate shared symmetric keys, with the security of these keys underpinned physically because they were established from the communication of quantum light signals.
(2) Quantum-resistant, or post-quantum cryptography (PQC), comprises new mathematical encryption techniques that are immune to attack by Shor’s algorithm and are thought to be resistant to other quantum algorithms that may be developed in the future. The National Institute of Standards and Technology (NIST) in the US is currently overseeing a worldwide process for the establishment of a suite of new PQC techniques, which will be made available for widespread use.
Quantum Communications Hub researchers are currently working on asymmetric PQC development and its hardware implementations. Work is also progressing on hybrid systems, integrating PQC with QKD for a future proof approach to quantum-safe communications. Hub investigators are also trialling the integration of PQC with quantum communications networks, to enable quantum-safe communications across longer distances via optical fibre.
NB Post-Quantum Cryptography is also commonly known as quantum-proof, quantum-safe or quantum-resistant cryptography.