The evolution of cloud technologies which allows the provisioning of IT resources over the Internet promises many benefits for the individuals and enterprises alike. However, this new resource provisioning model comes with the security challenges which did not exist in the traditional resource procurement mechanisms. We focus on the possible security concerns of a cloud user (e.g. an organization, government department, etc.) to lease cloud services such as resources in the form of Virtual Machines (VM) from a public Infrastructure-as-a-Service (IaaS) provider. There are many security critical areas in the cloud systems, such as data confidentiality, resource integrity, service compliance, security audits etc. In this thesis, we focus on the security aspects which result in the trust deficit among the cloud stakeholders and hence hinder a security sensitive user to benefit from the opportunities offered by the cloud computing. Based upon our findings from the security requirements analysis,we propose solutions that enable user trust in the public IaaS clouds. Our solutions mainly deal with the secure life cycle management of the user VM which include mechanisms for VM launch and migration. The VM launch and migration solutions ensure that the user VM is always protected in the cloud by only allowing it to run on the user trusted platforms. This is done by using trusted computing techniques that allow the users to remotely attest and hence rate the cloud platforms trusted or untrusted. We also provide a prototype implementation to prove the implementation feasibility of the proposed trust enabling principles used in the VM launch and migration solutions.

Les contremesures de masquage et de dissimulation permettent de rendre plus compliquées les attaques sur les implémentations de chiffrement symétrique. Elles sont aussi toutes deux aisément implémentables (et ce de façon automatisable) dans des flots EDA (Electronic Design Automation) pour ASIC (Application Specific Integrated Circuit) ou FPGA (Field Programmable Gates Array), avec certes différents niveaux d'expertise requis selon la contremesure concernée. Le masquage assure une protection "dynamique" s'appuyant sur un mélange d'aléa en cours de calcul. Nous montrons comment optimiser l'usage de cet aléa grâce à un codage qui permet de compresser les fuites d'information (leakage squeezing). Les limites du masquage s'étudient grâce à des outils de statistique, en analysant des distributions de probabilités. L'outil maître pour évaluer les imperfections des logiques DPL (Dual-rail with Precharge Logic style) est l'analyse stochastique, qui tente de modéliser des fuites "statiques" combinant plusieurs bits. L'inconvénient du masquage est que les attaques sont structurelles à l'utilisation d'aléa : si une attaque réussit sur une partie de la clé (e.g. un octet), alors a priori tous les autres octets sont de façon consistante vulnérables à la même attaque. La situation est différente avec les DPL : en cas de problème d'implémentation, seuls les octets de clés impliqués dans les parties déséquilibrées sont compromis, et non toute la clé. Une façon encore moins coûteuse de protéger les implémentations cryptographiques contre les attaques physiques est la résilience. C'est un usage astucieux de primitives a priori non protégées qui permet d'assurer la protection des secrets. L'avantage des approches résilientes est leur simplicité de mise en oeuvre et (idéalement), leur prouvabilité. Le principal inconvénient est que les contraintes d'usage ne sont souvent pas compatibles avec les standards actuels. Ainsi, nous pensons que davantage de recherche dans ce domaine pourrait globalement être profitable à l'industrie de la sécurité de systèmes embarqués.

The evolution of cloud computing allows the provisioning of IT resources over the Internet and promises many benefits for both - the service users and providers. Despite various benefits offered by cloud based services, many users hesitate in moving their IT systems to the cloud mainly due to many new security problems introduced by cloud environments. In fact, the characteristics of cloud computing become basis of new problems, for example, support of third party hosting introduces loss of user control on the hardware; similarly, on-demand availability requires reliance on complex and possibly insecure API interfaces; seamless scalability relies on the use of sub-providers; global access over public Internet exposes to broader attack surface; and use of shared resources for better resource utilization introduces isolation problems in a multi-tenant environment. These new security issues in addition to existing security challenges (that exist in today's classic IT environments) become major reasons for the lack of user trust in cloud based services categorized in Software-as-a-Service (SaaS), Platform-as-a-Service (PaaS) or Infrastructure-as-a-Service (IaaS). The focus of this thesis is on IaaS model which allows users to lease IT resources (e.g. computing power, memory, storage, etc.) from a public cloud to create Virtual Machine (VM) instances. The public cloud deployment model considered in this thesis exhibits most elasticity (i.e. degree of freedom to lease/release IT resources according to user demand) but is least secure as compared to private or hybrid models. As a result, public clouds are not trusted for many use cases which involve processing of security critical data such as health records, financial data, government data, etc. However, public IaaS clouds can also be made trustworthy and viable for these use cases by providing better transparency and security assurance services for the user. In this thesis, we consider such assurance services and identify security aspects which are important for making public clouds trustworthy. Based upon our findings, we propose solutions which promise to improve cloud transparency thereby realizing trustworthy clouds. The solutions presented in this thesis mainly deal with the secure life cycle management of the user VM which include protocols and their implementation for secure VM launch and migration. The VM launch and migration solutions ensure that the user VM is always hosted on correct cloud platforms which are setup according to a profile that fulfills the use case relevant security requirements. This is done by using an automated platform security audit and certification mechanism which uses trusted computing and security automation techniques in an integrated solution. In addition to provide the assurance about the cloud platforms, we also propose a solution which provides assurance about the placement of user data in correct and approved geographical locations which is critical from many legal aspects and usually an important requirement of the user. Finally, the assurance solutions provided in this thesis increase cloud transparency which is important for user trust and to realize trustworthy clouds.

Zugl.: Oldenburg, Universiẗat, Diss., 2009.

Zugleich: Diss. Mannheim, 2007. / Literaturverz.

This thesis aims to address several issues emerging in the new digital world. Using Trusted Computing as the paradigmatic example of regulation though code that tries to address the cyber security problem that occurs, where the freedom of the user to reconfigure her machine is restricted in exchange for greater, yet not perfect, security. Trusted Computing is a technology that while it aims to protect the user, and the integrity of her machine and her privacy against third party users, it discloses more of her information to trusted third parties, exposing her to security risks in case of compromising occurring to that third party. It also intends to create a decentralized, bottom up solution to security where security follows along the arcs of an emergent “network of trust”, and if that was viable, to achieve a form of code based regulation. Through the analysis attempted in this thesis, we laid the groundwork for a refined assessment, considering the problems that Trusted Computing Initiative (TCI) faces and that are based in the intentional, systematic but sometimes misunderstood and miscommunicated difference (which as we reveal results directly in certain design choices for TC) between the conception of trust in informatics (“techno-trust”) and the common sociological concept of it. To reap the benefits of TCI and create the dynamic “network of trust”, we need the sociological concept of trust sharing the fundamental characteristics of transitivity and holism which are absent from techno-trust. This gives rise to our next visited problems which are: if TC shifts the power from the customer to the TC provider, who takes on roles previously reserved for the nation state, then how in a democratic state can users trust those that make the rules? The answer lies partly in constitutional and human rights law and we drill into those functions of TC that makes the TCI provider comparable to state-like and ask what minimal legal guarantees need to be in place to accept, trustingly, this shift of power. Secondly, traditional liberal contract law reduces complex social relations to binary exchange relations, which are not transitive and disrupt rather than create networks. Contract law, as we argue, plays a central role for the way in which the TC provider interacts with his customers and this thesis contributes in speculating of a contract law that does not result in atomism, rather “brings in” potentially affected third parties and results in holistic networks. In the same vein, this thesis looks mainly at specific ways in which law can correct or redefine the implicit and democratically not validated shift of power from customer to TC providers while enhancing the social environment and its social trust within which TC must operate.

Trusted Computing Platform Alliance (TCPA), now known as Trusted Computing Group (TCG), is a trusted computing initiative created by IBM, Microsoft, HP, Compaq, Intel and several other smaller companies. Their goal is to create a secure trusted platform with help of new hardware and software. TCG have developed a new chip, the Trusted Platform Module (TPM) that is the core of this initiative, which is attached to the motherboard. An analysis is made on the TCG’s specifications and a summary is written of the different parts and functionalities implemented by this group. Microsoft is in the development stage for an operating system that can make use of TCG’s TPM and other new hardware. This initiative of the operating system is called NGSCB (Next Generation Secure Computing Base) former known as Palladium. This implementation makes use of TCG’s main functionalities with a few additions. An analysis is made on Microsoft’s NGSCB specifications and a summary is written of how this operating system will work. NGSCB is expected in Microsoft’s next operating system Longhorn version 2 that will have its release no sooner than 2006. Intel has developed hardware needed for a trusted platform and has come up with a template on how operating system developers should implement their OS to make use of this hardware. TCG’s TPM are also a part of the system. This system is called LaGrande. An analysis is also made on this trusted computing initiative and a sum up of it is written. This initiative is very similar to NGSCB, but Microsoft and Intel are not willing to comment on that. DRM (Digital Rights Management) is a technology that protects digital content (audio, video, documents, e-books etc) with rights. A DRM system is a system that manages the rights connected to the content and provides security for those by encryption. First, Microsoft’s RMS (Rights Management System) that controls the rights of documents within a company is considered. Second, a general digital media DRM system is considered that handles e-commerce for digital content. Analysis and discussion are made on what effects TC (Trusted Computing) and DRM could result in for home users, companies and suppliers of TC hardware and software. The different questions stated in the problemformulation is also discussed and considered. There are good and bad effects for every group but if TC will work as stated today, then the pros will outweigh the cons. The same goes for DRM on a TC platform. Since the benefits outweights the drawbacks, we think that TC should be fullfilled and taken into production. TC and DRM provides a good base of security and it is then up to the developers to use this in a good and responsible way.

This thesis describes the system design and implementation of the secure Ephemerizer System that was first introduced by Radia Perlman in 2005. The system is designed to enable users to keep data for a finite period of time before making the data unrecoverable by destroying the keys with which the data was encrypted. The task of the Ephemerizer System service is to create, advertise, and destroy keys required for the Ephemerizer System's functionalities. We designed the Ephemerizer System Service's security by placing the sensitive key management modules into a Trusted Computing Base (TCB). Our compartmentalized approach distributes security requirements at different sensitivity levels into different protection domains. In our approach, we implement the trusted protection domain (our TCB) on a tamper-resistant Javacard. We placed the key storage database into the partly trusted protection domain to improve scalability and availability of the Ephemerizer System. The partly trusted protection domain requires memory isolation and other security mechanisms provided by the underlying operating system. We implemented several mechanisms on the TCB, such as the signature engine, cryptographic modules, the on-card expiration validator, and on-card time verification. We make the Ephemerizer System available to users as a web service and expose it though a uniform API. This approach enables the seamless integration of the Ephemerizer System into business processes on heterogeneous platforms.

Large-scale deployment and use of cloud computing in industry is accompanied and in the same time hampered by concerns regarding protection of data handled by cloud computing providers. One of the consequences of moving data processing and storage off company premises is that organizations have less control over their infrastructure. As a result, cloud service (CS) clients must trust that the CS provider is able to protect their data and infrastructure from both external and internal attacks. Currently however, such trust can only rely on organizational processes declared by the CS provider and can not be remotely verified and validated by an external party. Enabling the CS client to verify the integrity of the host where the virtual machine instance will run, as well as to ensure that the virtual machine image has not been tampered with, are some steps towards building trust in the CS provider. Having the tools to perform such verifications prior to the launch of the VM instance allows the CS clients to decide in runtime whether certain data should be stored- or calculations should be made on the VM instance offered by the CS provider. This thesis combines three components -- trusted computing, virtualization technology and cloud computing platforms -- to address issues of trust and security in public cloud computing environments. Of the three components, virtualization technology has had the longest evolution and is a cornerstone for the realization of cloud computing. Trusted computing is a recent industry initiative that aims to implement the root of trust in a hardware component, the trusted platform module. The initiative has been formalized in a set of specifications and is currently at version 1.2. Cloud computing platforms pool virtualized computing, storage and network resources in order to serve a large number of customers customers that use a multi-tenant multiplexing model to offer on-demand self-service over broad network. Open source cloud computing platforms are, similar to trusted computing, a fairly recent technology in active development. The issue of trust in public cloud environments is addressed by examining the state of the art within cloud computing security and subsequently addressing the issues of establishing trust in the launch of a generic virtual machine in a public cloud environment. As a result, the thesis proposes a trusted launch protocol that allows CS clients to verify and ensure the integrity of the VM instance at launch time, as well as the integrity of the host where the VM instance is launched. The protocol relies on the use of Trusted Platform Module (TPM) for key generation and data protection. The TPM also plays an essential part in the integrity attestation of the VM instance host. Along with a theoretical, platform-agnostic protocol, the thesis also describes a detailed implementation design of the protocol using the OpenStack cloud computing platform. In order the verify the implementability of the proposed protocol, a prototype implementation has built using a distributed deployment of OpenStack. While the protocol covers only the trusted launch procedure using generic virtual machine images, it presents a step aimed to contribute towards the creation of a secure and trusted public cloud computing environment. / TESPEV / CNS

The aim of this thesis is to create a concept of semi-centralized cryptocurrency that supports external interoperability. It is assumed that semi-centralized cryptocurrency is the future of cryptocurrencies in the banking sector, because even at the cost of partial centralization, the concept brings the benefits of a decentralized ledger. Since the simultaneous deployment of their own cryptocurrencies by various central authorities, such as central bank, it is necessary to establish a communication protocol for interbank transactions. The work is thus focused on extending the existing Aquareum solution with an interoperability protocol.