Cryptography, theory

Information about individuals is collected by a variety of organizations including government agencies, banks, hospitals, research institutions, and private companies. In many cases, sharing this data among organizations can bring benefits in social, scientific, business, and security domains, as the collected information is of similar nature, of about similar populations. However, much of this collected data is sensitive as it contains personal information, or information that could damage an organization's reputation or competitiveness.

Secure computation allows users to collaboratively compute any program on their private data, while ensuring that they learn nothing beyond the output of the computation. Existing protocols for secure computation primarily rely on a boolean-circuit representation for the program being evaluated, which can be highly inefficient. This project focuses on developing secure-computation protocols in the RAM model of computation. Particularly challenging here is the need to ensure that memory accesses are oblivious, and do not leak information about private data.

The goal of the Modular Approach to Cloud Security (MACS) project is to develop methods for building information systems with meaningful multi-layered security guarantees. The modular approach of MACS focuses on systems that are built from smaller and separable functional components, where the security of each component is asserted individually, and where the security of the system as a whole can be derived from the security of its components. The project concentrates on building outsourced, cloud-based information services with client-centric security guarantees.

Cyber security is considered one of the most important aspects of our information technology based society. Key Exchange(KE) is a fundamental cryptographic primitive, and authenticated KE (AKE) is one of the most used cryptographic tools in secure communication protocols (e.g. SSL/TLS, IPSec, SSH) over the Internet. In light of the threat that quantum computers pose to cryptosystems such as RSA and ECC, this project is devoted to the development of secure and efficient AKE alternatives for the post-quantum computer world, which is now considered of a high priority by the US government.

Online security relies on communication protocols that establish trust and authentication. New protocols are created regularly, such as when Software-as-a-Service companies expose their software through new Web services. In the ideal case, network engineers and protocol experts collaborate to develop a protocol: one responsible for its efficiency and the other for its security. Unfortunately, this ideal is rarely realized.