Denial-of-Service Resistance in Key Establishment

Denial of Service (DoS) attacks are an increasing problem for network connected systems. Key establishment protocols are applications that are particularly vulnerable to DoS attack as they are typically required to perform computationally expensive cryptographic operations in order to authenticate the protocol initiator and to generate the cryptographic keying material that will subsequently be used to secure the communications between initiator and responder. The goal of DoS resistance in key establishment protocols is to ensure that attackers cannot prevent a legitimate initiator and responder deriving cryptographic keys without expending resources beyond a responder-determined threshold. In this work we review the strategies and techniques used to improve resistance to DoS attacks. Three key establishment protocols implementing DoS resistance techniques are critically reviewed and the impact of misapplication of the techniques on DoS resistance is discussed. Recommendations on effectively applying resistance techniques to key establishment protocols are made

Smart cards: State-of-the-art to future directions

The evolution of smart card technology provides an interesting case study of the relationship and interactions between security and business requirements. This paper maps out the milestones for smart card technology, discussing at each step the opportunities and challenges. The paper reviews recently proposed innovative ownership/management models and the security challenges associated with them. The paper concludes with a discussion of possible future directions for the technology, and the challenges these present

Authentication under Constraints

Authentication has become a critical step to gain access to services such as on-line banking, e-commerce, transport systems and cars (contact-less keys). In several cases, however, the authentication process has to be performed under challenging conditions. This thesis is essentially a compendium of five papers which are the result of a two-year study on authentication in constrained settings. The two major constraints considered in this work are: (1) the noise and (2) the computational power. For what concerns authentication under noisy conditions, Paper A and Paper B ad- dress the case in which the noise is in the authentication credentials. More precisely, the aforementioned papers present attacks against biometric authentication systems, that exploit the inherent variant nature of biometric traits to gain information that should not be leaked by the system. Paper C and Paper D study proximity- based authentication, i.e., distance-bounding protocols. In this case, both of the constraints are present: the possible presence of noise in the channel (which affects communication and thus the authentication process), as well as resource constraints on the computational power and the storage space of the authenticating party (called the prover, e.g., an RFID tag). Finally, Paper E investigates how to achieve reliable verification of the authenticity of a digital signature, when the verifying party has limited computational power, and thus offloads part of the computations to an untrusted server. Throughout the presented research work, a special emphasis is given to privacy concerns risen by the constrained conditions

Secure, Fast, and Energy-Efficient Outsourced Authentication for Smartphones

Common smartphone authentication mechanisms (e.g., PINs, graphical passwords, and fingerprint scans) are not designed to offer security post-login. Multi-modal continuous authentication addresses this issue by frequently and unobtrusively authenticating the user via behavioral biometric signals, such as touchscreen interaction and hand movements. Because smartphones can easily fall into the hands of the adversary, it is critical that the behavioral biometric information collected and processed on these devices is secured. This can be done by offloading encrypted template information to a remote server, and then performing authentication via privacy-preserving protocols. In this paper, we demonstrate that the energy overhead of current privacy-preserving protocols for continuous authentication is unsustainable on smartphones. To reduce energy consumption, we design a technique that leverages characteristics unique to the authentication setting in order to securely outsource computation to an untrusted Cloud. Our approach is secure against a colluding smartphone and Cloud, thus making it well suited for authentication. We performed extensive experimental evaluation. With our technique, the energy requirement for running an authentication instance that computes Manhattan distance is 0.2 mWh, which corresponds to a negligible fraction of the smartphone\u27s battery capacity. In addition, for Manhattan distance, our protocol runs in 0.72 and 2 s for 8 and 28 biometric features, respectively. We were also able to compute Hamming distance in 3.29 s, compared with 95.57 s achieved with the previous fastest outsourced computation protocol (Whitewash). These results demonstrate that ours is presently the only technique suitable for low-latency continuous authentication (e.g., with authentication scan windows of 60 s or shorter)

A comprehensive meta-analysis of cryptographic security mechanisms for cloud computing

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.The concept of cloud computing offers measurable computational or information resources as a service over the Internet. The major motivation behind the cloud setup is economic benefits, because it assures the reduction in expenditure for operational and infrastructural purposes. To transform it into a reality there are some impediments and hurdles which are required to be tackled, most profound of which are security, privacy and reliability issues. As the user data is revealed to the cloud, it departs the protection-sphere of the data owner. However, this brings partly new security and privacy concerns. This work focuses on these issues related to various cloud services and deployment models by spotlighting their major challenges. While the classical cryptography is an ancient discipline, modern cryptography, which has been mostly developed in the last few decades, is the subject of study which needs to be implemented so as to ensure strong security and privacy mechanisms in today’s real-world scenarios. The technological solutions, short and long term research goals of the cloud security will be described and addressed using various classical cryptographic mechanisms as well as modern ones. This work explores the new directions in cloud computing security, while highlighting the correct selection of these fundamental technologies from cryptographic point of view

Evidence acquisition in cloud forensics

In this paper, we present a performance comparison between different digital evidence acquisition protocols in the cloud-computing environment. We focus on data confidentiality, authenticity, and integrity issues