Quantum Cryptography

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Quantum information processing is concerned with what we can and cannot do with quantum information, which is the physical information that is held in the state of a quantum system, as predicted by quantum mechanics. Thanks to amazing phenomena such as entanglement, superposition, interference and no-cloning, quantum information revolutionizes the way we communicate and compute - enabling, for instance, ultra-fast computations and secure communications. Already, the technology for small-scale quantum computing exists; with continued effort, it is just a matter of time until full-scale quantum computing becomes a reality. The unprecedented computing power brought forth by quantum computers is known to completely break the cryptographic codes used to secure e-commerce. Fortunately, thanks to quantum key distribution (one of the earliest discoveries in quantum information processing), we know that quantum information enables a new level of security for communications, thwarting any attack by ultra-powerful devices.**As this example illustrates, we are sitting at a crossroads in terms of security: is the digital society ready for the advent of quantum computers?**My research aims at answering this question in the positive, ensuring that our information infrastructure remains both functional and secure in the presence of quantum information technologies. On one hand, I deal with the threats that stem from ultra-fast quantum computations, while on the other, I exploit the properties of quantum information in order to provide secure solutions. I shall explore two major questions; the first is the study of efficient methods of delegating private quantum computations, while the second asks if it is possible for a quantum program to hide its own inner workings.