Ubici: Bridging the gap between digital cryptography and the physical world

Advances in computing technologies increasingly blur the boundary between the digital domain and the physical world. Even though the research community has developed a large number of cryptographic primitives and has shown their usability in all-digital communication, many of them have not yet made their way into the real world. This work aims to make another step towards a tighter integration of digital cryptography into real world interactions. We first propose a security model that aims to model real-world attackers that have access to the physical channels between an actor and a token. We then describe Ubic, a framework that allows users to bridge the gap between digital cryptography and the physical world. The framework covers key cryptographic primitives, such as secure identification, document verification using a novel secure physical document format based on QR codes, as well as content hiding. Finally, we present an open-source implementation of our framework that is available to the community for further study and future extension.