How do you secure communications in the Quantum age?
More than ever, communication has become a critical aspect of our daily lives. From the simplest of businesses relying on an online presence to prosper, to people making purchases at a supermarket, to friends and family communicating through social media, tremendous information transfer occurs every second. Protecting this ever-increasing amount of information, one of the most valuable resources in the world, is ever more critical and complex.
Public-key infrastructure is used to distribute keys that protect almost all data transferred over the internet. The cryptography that underpins the security of this infrastructure is based on mathematical problems that are, for all practical purposes, infeasible to solve, even with substantial computational capability and time. However, quantum computers threaten to make the current key distribution techniques obsolete. So better ways of keeping information secure are needed. Much of today’s encrypted data is vulnerable to intercept-now-decrypt-later attacks, potentially jeopardizing business and governmental secrets.
The laws of quantum physics allow for new communication technologies with enhanced security properties. Quantum key distribution (QKD), the most important current candidate approach, enables distant parties to produce secret keys by sharing quantum systems with specific properties. Unlike public key-based techniques, where security is derived from computational hardness conjectures, in QKD, the uncertainty principle – which limits access to only certain information about physical systems; and entanglement – a type of physical correlation that only exists in the quantum world, provide security even against an all-powerful (computationally) adversary.
Reliably sharing quantum systems over long distances is the most critical challenge in the current quantum communication technology landscape. Quantum systems, typically in the form of photons, are precisely manipulated in terms of polarization, phase, etc., before transmission through quantum communication channels consisting of optical fibers for short ranges, and free space satellites links for long distances. Devices like quantum repeaters, placed in between communicating parties, will play an essential role in developing long-range quantum channels.
The integration of these technologies into existing network infrastructure has already begun. Moreover, research is being done towards quantum-based services beyond QKD, such as E-voting, secret sharing, digital signatures, and secure multiparty computation (a potent cryptographic tool that provides ways for multiple parties to perform joint computations on their private inputs, with a guarantee that their individual inputs stay hidden during the computation).
Every advance brings us closer to an interconnected world in which all our communications are protected through quantum-generated keys. Once we have access to such quantum internet, with the advances of traditional communication systems and the advent of the Internet of Things, we will live in a world where all people and their devices are constantly communicating among themselves securely. Ironically, this robust added layer of security is provided by the tiniest of particles, which is a beautiful thing to think about!