Developments in public-key encryption (PKE) and identity-based encryption (IBE) have revolutionized the field of cryptography and secure communication in general. PKE allowed remote parties to establish secure channels in front of eavesdropping adversaries, and led to public-key directories storing parties' public-keys. The stronger primitive of IBE eliminated the need for a large public-key directory, though this comes at the cost of trusting a central private-key generation authority. Decades after introduction of PKE and IBE, our understanding of the complexity of these tasks, in terms of what they can offer and the intractability assumptions needed for building them, is still very limited. At a high level, the goal of the project is to make progress exactly on these fronts. The project's novelties include a study of new cryptographic tools that give best of both IBE and PKE as well as developing new techniques for basing IBE and PKE on optimal intractability assumptions. The project impact is through new ways to secure communication. In addition, the collaboration between the investigators will help enhance the education of the graduate students at both institutes. More specifically, the goals of this project are pursued in two directions: (1) enhancements from minimal assumptions and (2) identifying barriers and proving lower bounds. The first direction of the project focuses on obtaining enhanced security for IBE and PKE from minimal assumptions. The efforts above on designing constructions from minimal assumptions would not be complete without having a formal understanding about when we have achieved optimal results. The second principal component of this project focuses on identifying those minimal assumptions. Specifically, the project's goal is to prove black-box and non-black-box barriers and (efficiency) lower bounds, complementing the results proved in the first direction.
SaTC: CORE: Medium: Collaborative: New Directions in Public-Key and Identity-Based Encryption