ADDING PERFECT FORWARD SECRECY TO KERBEROS

Kerberos system is a powerful and widely implemented authentication system. Despite this fact it has several problems such as the vulnerability to dictionary attacks which is solved with the use of public key cryptography. Also an important security feature that is not found in Kerberos is perfect forward secrecy. In this work the lack of this feature is investigated in Kerberos in its original version. Also a public key based modification to Kerberos is presented and it is shown that it lacks the prefect forward secrecy too. Then some extensions are proposed to achieve this feature. The extensions are based on public key concepts (Diffie-Hellman) with the condition of keeping the password based authentication; this requires little modifications to the original Kerberos. Four extensions are proposed; two of them modify the (Client-Authentication Server) exchange achieving conditional perfect forward secrecy, while the remaining two modify the Client-Server exchange achieving perfect forward secrecy but with increased overhead and delay

Unreliable Network Re-Authentication Protocol Based On Hybrid Key Using CSP Approach.

Network security is becoming increasingly vital in today's fast growing mobile computing environment. Due to constraints in device size and portability, limited processing power, small disk capacity, intermittent network disconnections and frequent switching between network access points have been observed in mobile devices

Authentication in Protected Core Networking

Protected Core Networking (PCN) is a concept that aims to increase information sharing between nations in coalition military operations. PCN specifies the interconnection of national transport networks, called Protected Core Segments (PCSs), to a federated transport network called Protected Core (PCore). PCore is intended to deliver high availability differentiated transport services to its user networks, called Colored Clouds (CCs). To achieve this goal, entity authentication of all connecting entities is specified as a protective measure. In resource constrained environments, the distribution of service policy can be challenging. That is, which transport services are associated with a given entity. The thesis proposes two new and original protocols where CCs push service policy to the network by performing authentication based on attributes. Using identity-based signatures, attributes constituting a service policy are used directly for an entity's identity, and no external mechanism linking identity and policy is needed. For interoperability, the idea has been incorporated into PKINIT Kerberos and symmetric key Kerberos by carrying the authorized attributes within tickets. The proposed protocols are formally verified in the symbolic model using scyther-proof. The experiment shows that both CCs, and PCSs achieve greater assurance on agreed attributes, and hence on expected service delivery. A CC and a visiting PCS are able to negotiate, and agree on the expected service depending on the situation. The proposed solution provides benefits to CCs on expected service when connecting to a visiting PCS, with poor connectivity to the home PCS. In that respect, interconnection of entities with little pre-established relationship is simplified, and hence fulfillment of the PCN concept is facilitated

Efficient key management protocols for mobile ad hoc networks

In this thesis, novel solutions are proposed for key management issues in mobile ad hoc networks. Presented Hierarchical Binary Tree (HBT) based model is distributed, self-organizing, scalable and does not employ online key distribution authority or group manager. Two different group authentication and group key establishment protocols are proposed for the users who form an ad hoc group with distributed trust model. Initially proposed protocols are based on public key cryptography and do not use specific algorithm. However, members can establish the keys faster with proposed customized hybrid scheme which combines elliptic curve cryptography, modular squaring operations and secret key encryption algorithm. Proposed HBT based model provides complete backward and forward security in case of modification in membership and it has comparable efficiency to the other HBT based schemes which employ real time key distribution authority. Mutual authentication and link encryption can be achieved in wireless sensor network only with public key cryptography if there are no pre-distributed keys. However, constraints in resources make fully public key operations not affordable on sensor. Three different authenticated key establishment protocols are proposed with an objective of being respectful to constraints. Sensor needs to make only modular or cyclic convolution multiplications, and expensive public key decryption operation is executed at the data processing station side. Schemes require small size of code and achieve the least sensor processing time in comparison with fully public key cryptography based protocols

Seluge++: A Secure Over-the-Air Programming Scheme in Wireless Sensor Networks

Over-the-air dissemination of code updates in wireless sensor networks have been researchers’ point of interest in the last few years, and, more importantly, security challenges toward the remote propagation of code updating have occupied the majority of efforts in this context. Many security models have been proposed to establish a balance between the energy consumption and security strength, having their concentration on the constrained nature of wireless sensor network (WSN) nodes. For authentication purposes, most of them have used a Merkle hash tree to avoid using multiple public cryptography operations. These models mostly have assumed an environment in which security has to be at a standard level. Therefore, they have not investigated the tree structure for mission-critical situations in which security has to be at the maximum possible level (e.g., military applications, healthcare). Considering this, we investigate existing security models used in over-the-air dissemination of code updates for possible vulnerabilities, and then, we provide a set of countermeasures, correspondingly named Security Model Requirements. Based on the investigation, we concentrate on Seluge, one of the existing over-the-air programming schemes, and we propose an improved version of it, named Seluge++, which complies with the Security Model Requirements and replaces the use of the inefficient Merkle tree with a novel method. Analytical and simulation results show the improvements in Seluge++ compared to Seluge

On the State of Crypto-Agility

The demand for crypto-agility, although dating back for more than two decades, recently started to increase in the light of the expected post-quantum cryptography (PQC) migration. Nevertheless, it started to evolve into a science on its own. Therefore, it is important to establish a unified definition of the notion, as well as its related aspects, scope, and practical applications. This paper presents a literature survey on crypto-agility and discusses respective development efforts categorized into different areas, including requirements, characteristics, and possible challenges. We explore the need for crypto-agility beyond PQC algorithms and security protocols and shed some light on current solutions, existing automation mechanisms, and best practices in this field. We evaluate the state of readiness for crypto-agility, and offer a discussion on the identified open issues. The results of our survey indicate a need for a comprehensive understanding. Further, more agile design paradigms are required in developing new IT systems, and in refactoring existing ones, in order to realize crypto-agility on a broad scale

Security and Performance Analysis for RFID Protocols

Radio Frequency Identification (RFID) is an advanced object identification technology that has already been applied in various industries. However, the insecure nature of the communication channel between readers and tags makes RFID systems vulnerable to various kinds of attacks. In recent years, many new methods have been proposed to improve the security of RFID systems, such as disabling tags, agent management and establishing cryptographic protocols. Among them, we focus on the last approach, which is more economic and convenient in certain cases. The first part of our work is to categorize typical existing RFID protocols according to their security levels. The result is vitally important to RFID system administrators who need to find different protocols to be implemented in their systems. The trade-off to be made in decision is that higher security level typically implies worse performance. We examine the performance in two aspects: the look-up cost in RFID reader’s back-end database and the tag-related cost. The tag-related cost includes the cryptographic operation cost (cryptographic computation cost along with access operatio

Multi-Base Chains for Faster Elliptic Curve Cryptography

This research addresses a multi-base number system (MBNS) for faster elliptic curve cryptography (ECC). The emphasis is on speeding up the main operation of ECC: scalar multiplication (tP). Mainly, it addresses the two issues of using the MBNS with ECC: deriving optimized formulas and choosing fast methods. To address the first issue, this research studies the optimized formulas (e.g., 3P, 5P) in different elliptic curve coordinate systems over prime and binary fields. For elliptic curves over prime fields, affine Weierstrass, Jacobian Weierstrass, and standard twisted Edwards coordinate systems are reviewed. For binary elliptic curves, affine, Lambda-projective, and twisted mu4-normal coordinate systems are reviewed. Additionally, whenever possible, this research derives several optimized formulas for these coordinate systems. To address the second issue, this research theoretically and experimentally studies the MBNS methods with respect to the average chain length, the average chain cost, and the average conversion cost. The reviewed MBNS methods are greedy, ternary/binary, multi-base NAF, tree-based, and rDAG-based. The emphasis is on these methods\u27 techniques to convert integer t to multi-base chains. Additionally, this research develops bucket methods that advance the MBNS methods. The experimental results show that the MBNS methods with the optimized formulas, in general, have good improvements on the performance of scalar multiplication, compared to the single-base number system methods

Data Protection for the Internet of Things

The Internet of Things (abbreviated: “IoT”) is acknowledged as one of the most important disruptive technologies with more than 16 billion devices forecasted to interact autonomously by 2020. The idea is simple, devices will help to measure the status of physical objects. The devices, containing sensors and actuators, are so small that they can be integrated or attached to any object in order to measure that object and possibly change its status accordingly. A process or work flow is then able to interact with those devices and to control the objects physically. The result is the collection of massive data in a ubiquitous form. This data can be analysed to gain new insights, a benefit propagated by the “Big Data” and “Smart Data” paradigms. While governments, cities and industries are heavily involved in the Internet of Things, society’s privacy awareness and the concerns over data protection in IoT increase steadily. The scale of the collection, processing and dissemination of possibly private information in the Internet of Things has long begun to raise privacy concerns. The problem is a fundamental one, it is the massive data collection that benefits the investment on IoT, while it contradicts the interest on data minimization coming from privacy advocates. And the challenges go even further, while privacy is an actively researched topic with a mature variety of privacy preserving mechanisms, legal studies and surveillance studies in specific contexts, investigations of how to apply this concepts in the constrained environment of IoT have merely begun. Thus the objective of this thesis is threefold and tackles several topics, looking at them in a differentiated way and later bringing them together for one of the first, (more) complete pictures of privacy in IoT. The first starting point is the throughout study of stakeholders, impact areas and proposals on an architectural reference model for IoT. At the time of this writing, IoT was adversed heavily by several companies, products and even governments, creating a blurred picture of what IoT really is. This thesis surveys stakeholders, scenarios, architecture paradigms and definitions to find a working definition for IoT which adequately describes the intersection between all of the aforementioned topics. In a further step, the definition is applied exemplary on two scenarios to identify the common building blocks of those scenarios and of IoT in general. The building blocks are then verified against a similar approach by the IoT-A and Rerum projects and unified to an IoT domain model. This approach purposefully uses notions and paradigms provided in related scientific work and European projects in order to benefit from existing efforts and to achieve a common understanding. In this thesis, the observation of so called cyber-physical properties of IoT leads to the conclusion that IoT proposals miss a core concept of physical interaction in the “real world”. Accordingly, this thesis takes a detour to jurisdiction and identifies ownership and possession as a main concept of “human-to-object” relationships. The analysis of IoT building blocks ends with an enhanced IoT domain model. The next step breaks down “privacy by design”. Notably hereby is that privacy by design has been well integrated in to the new European General Data Protection Regulation (GDPR). This regulation heavily affects IoT and thus serves as the main source of privacy requirements. Gürses et al.’s privacy paradigm (privacy as confidentiality, privacy as control and privacy as practice) is used for the breakdown, preceded by a survey of relevant privacy proposals, where relevancy was measured upon previously identified IoT impact areas and stakeholders. Independently from IoT, this thesis shows that privacy engineering is a task that still needs to be well understood. A privacy development lifecycle was therefore sketched as a first step in this direction. Existing privacy technologies are part of the survey. Current research is summed up to show that while many schemes exist, few are adequate for actual application in IoT due to their high energy or computational consumption and high implementation costs (most notably caused by the implementation of special arithmetics). In an effort to give a first direction on possible new privacy enhancing technologies for IoT, new technical schemes are presented, formally verified and evaluated. The proposals comprise schemes, among others, on relaxed integrity protection, privacy friendly authentication and authorization as well as geo-location privacy. The schemes are presented to industry partners with positive results. This technologies have thus been published in academia and as intellectual property items. This thesis concludes by bringing privacy and IoT together. The final result is a privacy enhanced IoT domain model accompanied by a set of assumptions regarding stakeholders, economic impacts, economic and technical constraints as well as formally verified and evaluated proof of concept technologies for privacy in IoT. There is justifiable interest in IoT as it helps to tackle many future challenges found in several impact areas. At the same time, IoT impacts the stakeholders that participate in those areas, creating the need for unification of IoT and privacy. This thesis shows that technical and economic constraints do not impede such a process, although the process has merely begun