• Foundations of Cryptography

    In this group, we study the theoretical foundations of modern cryptography. The fundamental question to be answered here is which cryptographic constructs exist, and under what complexity-theoretic assumptions. The main focus is on primitives such as one-way functions, pseudorandom generators, and encryption and signature schemes, as well as cryptographic protocols such authentication, zero-knowledge, and secure multiparty protocols. Efficient realization of provably-secure constructs is another important issue to consider.

  • Computational Trust and Uncertainty Management

    Trust is an important concept in interpersonal relationships. It is a soft replacement for strict control mechanisms which helps individuals to have a better estimation of the risks involved in an interaction or relationship. Different computational models of trust have been proposed that quantify the degree of trust between agents/entities in a multi-agent environment. This quantity which we call the trust value, is further utilized to regulate interactions in the environment. Computational trust models have been successfully applied to collaborative, recommendation and filtering systems, as well as in lower level systems such as message routing.
    Based on this background, the trust research group in DNSL investigates various problems in computational trust and trust-based systems. Our main area of research is about ignoring or incorrectly handling of uncertainty. We are to detect the types of uncertainty and their factors in trust, correctly model the uncertainties, and adjust the uncertainty according to the requirements of the application. In summary, we do/have done research in the following areas:
       • Uncertainty and its management in computational trust,
       • Trust inference in social networks,
       • Attacks on trust-based systems and mitigation techniques,
       •  Privacy in trust-based systems,
       • New (security) applications of trust for example in database outsourcing.

  • Outsourced Database security
  • Nowadays, outsourcing is very popular, including outsourcing the Data and querying of databases to untrusted servers.