Governments depend on encryption for a vast range of critical data, from managing tax returns online to coordinating counter-terrorism operations. However, today’s public key encryption is already known to be vulnerable to future quantum attacks, creating major security risks that will grow with time. Quantum safe approaches, including QKD, a mature quantum technology for the distribution of encryption keys, will be needed to secure future communications. Public services – from tax payments, to healthcare, to driving licence applications – are increasingly managed online. Future smart grids will use encryption to prevent cyber-attacks. Any discussions about e-voting depend on voter data being encrypted. These will all be compromised if current encryption can be cracked. Organised malicious actors and nation states are already collecting encrypted information with the plan to crack it later. So, there is already an imperative to adopt “quantum safe” security in some cases, such as when sharing national security data that needs to stay secret for 20 years or more.

In parallel to the development of quantum communications, research and development is also being pursued with other forms of “quantum-safe” communications – secure against eavesdroppers or adversaries armed with arbitrarily powerful quantum computers or sensors working at the absolute quantum limit. One such direction is with new mathematical approaches, called quantum-resistant or post-quantum cryptography (PQC), which are known to be immune to current quantum computer algorithms and thought to be immune to any that might be developed in the future. It is anticipated that the most flexible and secure communications in the future will incorporate both QKD and PQC.