Auflistung nach Autor:in "Rizk, Amr"
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- KonferenzbeitragThe Bitcoin Universe: An Architectural Overview of the Bitcoin Blockchain(11. DFN-Forum Kommunikationstechnologien, 2018) Müller, Paul; Bergsträßer, Sonja; Rizk, Amr; Steinmetz, RalfOn January 2009, the emergence of Bitcoin surprised theworld with a new idea involving decentralized secure money transfers outside the ecosystem of FIAT currencies. The concepts behind the Bitcoin architecture the blockchain can, however, be extended to a much wider range of economic assets than just digital currencies. In general, a blockchain is a distributed, verifiable database, which operates through a confluence of public-key cryptography, the concept of proof of work and P2P-systems.
- ZeitschriftenartikelBrokerless inter-domain virtual network embedding: A blockchain-based approach(it - Information Technology: Vol. 60, No. 5-6, 2018) Rizk, Amr; Bisbal, Jordi; Bergsträßer, Sonja; Steinmetz, RalfThe blockchain technology enables entities to query and alter information without trusting a middle party while providing a secure data storage in a decentralized manner. In this paper, we focus on an IT data supply chain scenario, where multiple actors negotiate a tenancy agreement for virtualized network resources. This process consists of service providers (SPs) requesting the embedding of specified virtual networks across multiple infrastructure providers (InPs). Since InPs are typically not willing to disclose detailed internal network information, this is a major deal breaker that hampers the efficiency of the service negotiation process. After reviewing the related work on centralized and decentralized virtual network embedding (VNE) approaches, we briefly discuss the reasons for a blockchain approach for this problem. Our approach comprises of a brokerless blockchain based system, that uses smart contracts and a VN partitioning algorithm based on the Vickrey auction model. Finally, we investigate the feasibility of our approach, by first analyzing the behavior of the introduced auction model in adverse conditions and by secondly evaluating the blockchain performance given different consensus protocols.
- TextdokumentNicht-asymptotische Leistungsbewertung und abtastbasierte Parameterschätzung für Kommunikationsnetzwerke mit langzeitkorreliertem Datenverkehr(Ausgezeichnete Informatikdissertationen 2013, 2014) Rizk, Amr
- KonferenzbeitragResilience in Security and Crises through Adaptions and Transitions(INFORMATIK 2019: 50 Jahre Gesellschaft für Informatik – Informatik für Gesellschaft (Workshop-Beiträge), 2019) Kalle, Timo; Kaufhold, Marc-André; Kuntke, Franz; Reuter, Christian; Rizk, Amr; Steinmetz, RalfCurrently, there is a tremendous number of communication technology and systems in use. Not only in the private user space, but also in business operations and societal areas, they are deeply involved: Ranging from messaging services or navigation over (critical) SCADA systems to whole digital cities and communities. Consequently, the view on communication networks in security and particularly crisis scenarios becomes inevitable. This paper examines the notions of resilience, adaption and transition within communication networks with a specific focus on crises. Based on a structured literature review, the fundamentals of resilience and communication networks are introduced. The paper then discusses the characteristics of (a) evolvability, accessibility, usability and diversity as well as (b) self-organization, -management, -optimization, - monitoring, -healing and -protection for communication network resilience. Finally, it outlines challenges and potentials of communication network resilience based in the use cases of security and crises.