State and Randomness Leakage Resilient and Privacy-Preserving Key Exchange

Authenticated Key Exchange (AKE) is and has always been an important research topic in the field of cryptography. Due to the emerging of new computing environment such as the virtualization in cloud computing, and the increasing awareness of user privacy, new attacks involving the maliciously controlled or reused randomness have become real threats, and new security requirements such as privacy-preserving communications over heterogeneous networks have become predominant features to be fulfilled. For example, adversarial reset of Virtual Machines (VMs) in cloud computing has been shown to be a serious security threat which could lead to the leakage of long-term secret keys of AKE protocols. In this project, we focus on two aspects of AKE protocols. The first aspect is the formalization and construction of (Password-based) AKE security models and protocols, respectively, for scenarios where various leakage related attacks are considered that include session state reveal, ephemeral key leakage, and bad or reused randomness. The second aspect is on the privacy-preserving AKE protocols which ensure the untraceability and anonymity of entities when multiple sessions of AKE protocols are carried out by the same entity with different entities across a heterogeneous network. Such a network is becoming more popular nowadays as users can roam across various types of wireless networks such as 4G cellular data networks and WiFi hotspots. As a continuing emerging field in cryptography, we observe that AKE has many new security threats and also a wide range of interesting research problems. We focus our attention on these research problems in authenticated key exchange because of their importance in both theory and practice, as well as the expertise of our research team.