Foundations and Applications of Resource-Restricted Cryptography

In modern cryptography most schemes come with a security proof showing that there is no attack using an amount of resources that could realistically be acquired by a potential adversary. An exception to this rule are cryptographic protocols that rely on problems that deliberately are only "moderately hard" to break: they can be practically solved, but require significant resources like computation, (disk/memory) space or time. Examples include proofs of work as used in Bitcoin mining, or memory-hard functions used for password hashing.

There are currently few applications of such resource restricted cryptography (RRC) and the existing theory is not nearly as well developed as in the "classical" setting.

This project brings together researchers who work on cryptographic proof techniques, privacy, and the design of cryptographic primitives and protocols, to build the foundations and expand the realm of RRC. Our central hypothesis is that RRC has the potential to address many protocol problems, including tasks that are provably impossible to solve in the classical setting. A special focus of this project is on privacy (rather than just security), where currently RRC has found almost no applications.

The project is organized in three intertwined objectives. The first is addressing the foundations of RRC, the second is concerned with the definitions and constructions of RRC building blocks, while the last objective is on constructing protocols leveraging RRC to achieve security and privacy.