Practice-Oriented Techniques in Lattice-Based Cryptography

In today’s computerised world, billions of people rely heavily on security systems that protect a tremendous amount of sensitive information ranging from banking information to government secrets. The algorithms currently used in such systems rely on classical cryptographic assumptions that do not provide security against powerful quantum computers. In this thesis, new techniques in lattice-based cryptography, one of the most promising candidates for quantum-safe cryptography, are explored with a practice-oriented approach in mind. A particular focus is on privacy-preserving protocols and their higher level applications. To this end, the thesis starts from building foundational techniques and proceeds towards practical schemes, constructing a full-fledged quantum-safe blockchain protocol in the end.