A scalable and dynamic application-level secure communication framework for inter-cloud services

Most of the current cloud computing platforms offer Infrastructure as a Service (IaaS) model, which aims to provision basic virtualized computing resources as on-demand and dynamic services. Nevertheless, a single cloud does not have limitless resources to offer to its users, hence the notion of an Inter-Cloud environment where a cloud can use the infrastructure resources of other clouds. However, there is no common framework in existence that allows the service owners to seamlessly provision even some basic services across multiple cloud service providers, albeit not due to any inherent incompatibility or proprietary nature of the foundation technologies on which these cloud platforms is built. In this paper we present a novel solution which aims to cover a gap in a subsection of this problem domain. Our solution offers a security architecture that enables service owners to provision a dynamic and service-oriented secure virtual private network on top of multiple cloud IaaS providers. It does this by leveraging the scalability, robustness and exibility of peer-to-peer overlay techniques to eliminate the manual configuration, key management and peer churn problems encountered in setting up the secure communication channels dynamically, between different components of a typical service that is deployed on multiple clouds. We present the implementation details of our solution as well as experimental results carried out on two commercial clouds

Client-side privacy-enhancing technologies in web search

Els motors de cerca (En anglès, Web Search Engines - WSEs-), són eines que permeten als usuaris localitzar informació específica a Internet. Un dels objectius dels WSEs és retornar els resultats que millor coincideixen amb els interessos de cada usuari. Amb aquesta finalitat, l'WSEs recull i analitza l' historial de cerca per construir perfils. Com a resultat, un usuari que envia una certa consulta rebrà els resultats més interessants en les primeres posicions. Encara que proporcionen un servei molt útil, també representen una amenaça per a la privacitat dels seus usuaris. Es construeixen els perfils basats en la història de les consultes i altres dades relacionades que poden contenir informació personal i privada. Per evitar aquesta amenaça de privacitat, és necessari establir mecanismes per a la protecció de la privacitat dels usuaris dels motors de cerca. Actualment, hi ha diverses solucions en la literatura per proporcionar privacitat a aquests usuaris. Un dels objectius d'aquest estudi és analitzar les solucions existents, estudiar les seves diferències i els avantatges i inconvenients de cada proposta. Llavors, basat en l'estat de l'art, presentem noves propostes per protegir la privadesa dels usuaris. Més concretament, aquesta tesi proposa tres protocols per preservar la privacitat dels usuaris en la cerca web. La idea general és distribuir als usuaris en grups on intercanvi consultes, com a mètode d'ofuscació ocultar les consultes reals de cada usuari. El primer protocol distribuït que proposem es centra en la reducció del temps d'espera de consulta, és a dir, el temps que cada membre del grup ha d'esperar per rebre els resultats de la seva consulta. El segon protocol proposat millora les propostes anteriors ja que resisteix els atacs interns, i obté millors resultats que les propostes similars en termes de càlcul i comunicació. La tercera proposta és un protocol P2P, on els usuaris estan agrupats segons les seves preferències. Això permet ocultar els perfils d'usuari però conservar els interessos generals. En conseqüència, el motor de cerca és capaç de classificar millor els resultats de les seves consultes.Los motores de búsqueda (en inglés, Web Search Engines -WSEs-) son herramientas que permiten a los usuarios localizar información específica en Internet. Uno de los objetivos de los WSEs es devolver los resultados que mejor coinciden con los intereses de cada usuario. Para ello, los WSEs recogen y analizan el historial de búsqueda de los usuarios para construir perfiles. Como resultado, un usuario que envía una cierta consulta recibirá los resultados más interesantes en las primeras posiciones. Aunque ofrecen un servicio muy útil, también representan una amenaza para la privacidad de sus usuarios. Los perfiles se construyen a partir del historial de consultas y otros datos relacionados que pueden contener información privada y personal. Para evitar esta amenaza de privacidad, es necesario establecer mecanismos de protección de privacidad de motores de búsqueda. En la actualidad, existen varias soluciones en la literatura para proporcionar privacidad a estos usuarios. Uno de los objetivos de este trabajo es examinar las soluciones existentes, analizando sus diferencias y las ventajas y desventajas de cada propuesta. Después, basándonos en el estado del arte actual, presentamos nuevas propuestas que protegen la privacidad de los usuarios. Más concretamente, esta tesis doctoral propone tres protocolos que preservan la privacidad de los usuarios en las búsquedas web. La idea general es distribuir a los usuarios en grupos donde intercambian sus consultas, como método de ofuscación para ocultar las consultas reales de cada usuario. El primer protocolo distribuido que proponemos se centra en reducir el tiempo de espera de la consulta, es decir, el tiempo que cada miembro del grupo tiene que esperar para recibir los resultados de la consulta. El segundo protocolo propuesto mejora anteriores propuestas porque resiste ataques internos, mejorando propuestas similares en términos de cómputo y comunicación. La tercera propuesta es un protocolo P2P, donde los usuarios se agrupan según sus preferencias. Esto permite ofuscar los perfiles de los usuarios pero conservando a sus intereses generales. En consecuencia, el WSE es capaz de clasificar mejor los resultados de sus consultas.Web search engines (WSEs) are tools that allow users to locate specific information on the Internet. One of the objectives of WSEs is to return the results that best match the interests of each user. For this purpose, WSEs collect and analyze users’ search history in order to build profiles. Consequently, a profiled user who submits a certain query will receive the results which are more interesting for her in the first positions. Although they offer a very useful service, they also represent a threat for their users’ privacy. Profiles are built from past queries and other related data that may contain private and personal information. In order to avoid this privacy threat, it is necessary to provide privacy-preserving mechanisms that protect users. Nowadays, there exist several solutions that intend to provide privacy in this field. One of the goals of this work is to survey the current solutions, analyzing their differences and remarking the advantages and disadvantages of each approach. Then, based on the current state of the art, we present new proposals that protect users’ privacy. More specifically, this dissertation proposes three different privacy-preserving multi-party protocols for web search. A multi-party protocol for web search arranges users into groups where they exchange their queries. This serves as an obfuscation method to hide the real queries of each user. The first multi-party protocol that we propose focuses on reducing the query delay. This is the time that every group member has to wait in order to receive the query results. The second proposed multi-party protocol improves current literature because it is resilient against internal attacks, outperforming similar proposals in terms of computation and communication. The third proposal is a P2P protocol, where users are grouped according to their preferences. This allows to obfuscate users’ profiles but conserving their general interests. Consequently, the WSE is able to better rank the results of their queries

A secure and scalable communication framework for inter-cloud services

A lot of contemporary cloud computing platforms offer Infrastructure-as-a-Service provisioning model, which offers to deliver basic virtualized computing resources like storage, hardware, and networking as on-demand and dynamic services. However, a single cloud service provider does not have limitless resources to offer to its users, and increasingly users are demanding the features of extensibility and inter-operability with other cloud service providers. This has increased the complexity of the cloud ecosystem and resulted in the emergence of the concept of an Inter-Cloud environment where a cloud computing platform can use the infrastructure resources of other cloud computing platforms to offer a greater value and flexibility to its users. However, there are no common models or standards in existence that allows the users of the cloud service providers to provision even some basic services across multiple cloud service providers seamlessly, although admittedly it is not due to any inherent incompatibility or proprietary nature of the foundation technologies on which these cloud computing platforms are built. Therefore, there is a justified need of investigating models and frameworks which allow the users of the cloud computing technologies to benefit from the added values of the emerging Inter-Cloud environment. In this dissertation, we present a novel security model and protocols that aims to cover one of the most important gaps in a subsection of this field, that is, the problem domain of provisioning secure communication within the context of a multi-provider Inter-Cloud environment. Our model offers a secure communication framework that enables a user of multiple cloud service providers to provision a dynamic application-level secure virtual private network on top of the participating cloud service providers. We accomplish this by taking leverage of the scalability, robustness, and flexibility of peer-to-peer overlays and distributed hash tables, in addition to novel usage of applied cryptography techniques to design secure and efficient admission control and resource discovery protocols. The peer-to-peer approach helps us in eliminating the problems of manual configurations, key management, and peer churn that are encountered when setting up the secure communication channels dynamically, whereas the secure admission control and secure resource discovery protocols plug the security gaps that are commonly found in the peer-to-peer overlays. In addition to the design and architecture of our research contributions, we also present the details of a prototype implementation containing all of the elements of our research, as well as showcase our experimental results detailing the performance, scalability, and overheads of our approach, that have been carried out on actual (as opposed to simulated) multiple commercial and non-commercial cloud computing platforms. These results demonstrate that our architecture incurs minimal latency and throughput overheads for the Inter-Cloud VPN connections among the virtual machines of a service deployed on multiple cloud platforms, which are 5% and 10% respectively. Our results also show that our admission control scheme is approximately 82% more efficient and our secure resource discovery scheme is about 72% more efficient than a standard PKI-based (Public Key Infrastructure) scheme

Secure Schemes for Semi-Trusted Environment

In recent years, two distributed system technologies have emerged: Peer-to-Peer (P2P) and cloud computing. For the former, the computers at the edge of networks share their resources, i.e., computing power, data, and network bandwidth, and obtain resources from other peers in the same community. Although this technology enables efficiency, scalability, and availability at low cost of ownership and maintenance, peers defined as ``like each other'' are not wholly controlled by one another or by the same authority. In addition, resources and functionality in P2P systems depend on peer contribution, i.e., storing, computing, routing, etc. These specific aspects raise security concerns and attacks that many researchers try to address. Most solutions proposed by researchers rely on public-key certificates from an external Certificate Authority (CA) or a centralized Public Key Infrastructure (PKI). However, both CA and PKI are contradictory to fully decentralized P2P systems that are self-organizing and infrastructureless. To avoid this contradiction, this thesis concerns the provisioning of public-key certificates in P2P communities, which is a crucial foundation for securing P2P functionalities and applications. We create a framework, named the Self-Organizing and Self-Healing CA group (SOHCG), that can provide certificates without a centralized Trusted Third Party (TTP). In our framework, a CA group is initialized in a Content Addressable Network (CAN) by trusted bootstrap nodes and then grows to a mature state by itself. Based on our group management policies and predefined parameters, the membership in a CA group is dynamic and has a uniform distribution over the P2P community; the size of a CA group is kept to a level that balances performance and acceptable security. The muticast group over an underlying CA group is constructed to reduce communication and computation overhead from collaboration among CA members. To maintain the quality of the CA group, the honest majority of members is maintained by a Byzantine agreement algorithm, and all shares are refreshed gradually and continuously. Our CA framework has been designed to meet all design goals, being self-organizing, self-healing, scalable, resilient, and efficient. A security analysis shows that the framework enables key registration and certificate issue with resistance to external attacks, i.e., node impersonation, man-in-the-middle (MITM), Sybil, and a specific form of DoS, as well as internal attacks, i.e., CA functionality interference and CA group subversion. Cloud computing is the most recent evolution of distributed systems that enable shared resources like P2P systems. Unlike P2P systems, cloud entities are asymmetric in roles like client-server models, i.e., end-users collaborate with Cloud Service Providers (CSPs) through Web interfaces or Web portals. Cloud computing is a combination of technologies, e.g., SOA services, virtualization, grid computing, clustering, P2P overlay networks, management automation, and the Internet, etc. With these technologies, cloud computing can deliver services with specific properties: on-demand self-service, broad network access, resource pooling, rapid elasticity, measured services. However, theses core technologies have their own intrinsic vulnerabilities, so they induce specific attacks to cloud computing. Furthermore, since public clouds are a form of outsourcing, the security of users' resources must rely on CSPs' administration. This situation raises two crucial security concerns for users: locking data into a single CSP and losing control of resources. Providing inter-operations between Application Service Providers (ASPs) and untrusted cloud storage is a countermeasure that can protect users from lock-in with a vendor and losing control of their data. To meet the above challenge, this thesis proposed a new authorization scheme, named OAuth and ABE based authorization (AAuth), that is built on the OAuth standard and leverages Ciphertext-Policy Attribute Based Encryption (CP-ABE) and ElGamal-like masks to construct ABE-based tokens. The ABE-tokens can facilitate a user-centric approach, end-to-end encryption and end-to-end authorization in semi-trusted clouds. With these facilities, owners can take control of their data resting in semi-untrusted clouds and safely use services from unknown ASPs. To this end, our scheme divides the attribute universe into two disjointed sets: confined attributes defined by owners to limit the lifetime and scope of tokens and descriptive attributes defined by authority(s) to certify the characteristic of ASPs. Security analysis shows that AAuth maintains the same security level as the original CP-ABE scheme and protects users from exposing their credentials to ASP, as OAuth does. Moreover, AAuth can resist both external and internal attacks, including untrusted cloud storage. Since most cryptographic functions are delegated from owners to CSPs, AAuth gains computing power from clouds. In our extensive simulation, AAuth's greater overhead was balanced by greater security than OAuth's. Furthermore, our scheme works seamlessly with storage providers by retaining the providers' APIs in the usual way

STAIBT: Blockchain and CP-ABE Empowered Secure and Trusted Agricultural IoT Blockchain Terminal

The integration of agricultural Internet of Things (IoT) and blockchain has become the key technology of precision agriculture. How to protect data privacy and security from data source is one of the difficult issues in agricultural IoT research. This work integrates cryptography, blockchain and Interplanetary File System (IPFS) technologies, and proposes a general IoT blockchain terminal system architecture, which strongly supports the integration of the IoT and blockchain technology. This research innovatively designed a fine-grained and flexible terminal data access control scheme based on the ciphertext-policy attribute-based encryption (CP-ABE) algorithm. Based on CP-ABE and DES algorithms, a hybrid data encryption scheme is designed to realize 1-to-N encrypted data sharing. A "horizontal + vertical" IoT data segmentation scheme under blockchain technology is proposed to realize the classified release of different types of data on the blockchain. The experimental results show that the design scheme can ensure data access control security, privacy data confidentiality, and data high-availability security. This solution significantly reduces the complexity of key management, can realize efficient sharing of encrypted data, flexibly set access control strategies, and has the ability to store large data files in the agricultural IoT

A patient agent controlled customized blockchain based framework for internet of things

Although Blockchain implementations have emerged as revolutionary technologies for various industrial applications including cryptocurrencies, they have not been widely deployed to store data streaming from sensors to remote servers in architectures known as Internet of Things. New Blockchain for the Internet of Things models promise secure solutions for eHealth, smart cities, and other applications. These models pave the way for continuous monitoring of patient’s physiological signs with wearable sensors to augment traditional medical practice without recourse to storing data with a trusted authority. However, existing Blockchain algorithms cannot accommodate the huge volumes, security, and privacy requirements of health data. In this thesis, our first contribution is an End-to-End secure eHealth architecture that introduces an intelligent Patient Centric Agent. The Patient Centric Agent executing on dedicated hardware manages the storage and access of streams of sensors generated health data, into a customized Blockchain and other less secure repositories. As IoT devices cannot host Blockchain technology due to their limited memory, power, and computational resources, the Patient Centric Agent coordinates and communicates with a private customized Blockchain on behalf of the wearable devices. While the adoption of a Patient Centric Agent offers solutions for addressing continuous monitoring of patients’ health, dealing with storage, data privacy and network security issues, the architecture is vulnerable to Denial of Services(DoS) and single point of failure attacks. To address this issue, we advance a second contribution; a decentralised eHealth system in which the Patient Centric Agent is replicated at three levels: Sensing Layer, NEAR Processing Layer and FAR Processing Layer. The functionalities of the Patient Centric Agent are customized to manage the tasks of the three levels. Simulations confirm protection of the architecture against DoS attacks. Few patients require all their health data to be stored in Blockchain repositories but instead need to select an appropriate storage medium for each chunk of data by matching their personal needs and preferences with features of candidate storage mediums. Motivated by this context, we advance third contribution; a recommendation model for health data storage that can accommodate patient preferences and make storage decisions rapidly, in real-time, even with streamed data. The mapping between health data features and characteristics of each repository is learned using machine learning. The Blockchain’s capacity to make transactions and store records without central oversight enables its application for IoT networks outside health such as underwater IoT networks where the unattended nature of the nodes threatens their security and privacy. However, underwater IoT differs from ground IoT as acoustics signals are the communication media leading to high propagation delays, high error rates exacerbated by turbulent water currents. Our fourth contribution is a customized Blockchain leveraged framework with the model of Patient-Centric Agent renamed as Smart Agent for securely monitoring underwater IoT. Finally, the smart Agent has been investigated in developing an IoT smart home or cities monitoring framework. The key algorithms underpinning to each contribution have been implemented and analysed using simulators.Doctor of Philosoph