Service-centric Networking

Prof. Dr. Axel Küpper






Office TEL19
Building TEL
Address Ernst - Reuter - Platz 7
10587 Berlin


Kindly note - no office hours will be provided from July 27 to August 10, 2022!

Please be informed that our office hours will be provided every Wednesday from 12:00 - 13:00. Please register at the secretariat.



S. Göndör, Yildiz, M. Westerkamp and A. Küpper, "Blade: A Blockchain-supported Architecture for Decentralized Services" in 4th IEEE International Conference on Decentralized Application and Infrastructures, IEEE, 2022.

Decentralized services and applications provide a multitude of advantages for their users, such as improved privacy, control, and independence from third parties. Anyhow, decentralization comes at the cost of certain disadvantages, such as increased application complexity or communication overhead. This aggravates the development and deployment of decentralized services and applications. In this paper we present Blade, a software platform that aims to ease the effort of development and deployment of decentralized services by implementing reusable solutions for recurring challenges developers are facing when designing decentralized service architectures. Blade implements such functionality in a Blade server instance, which can be deployed on a lightweight device, such as a NAS, Raspberry Pi, or router at home. This allows users without expert knowledge to run a Blade instance with already existing hardware with little overhead. Blade supports polyglot Blade modules that implement extended functionality, such as interfaces, frontends, and business logic of decentralized applications. %, e.g. a decentralized instant messaging service or an online social network. Blade modules are installed via a decentralized, Ethereum-based marketplace that can be accessed via the Blade instances. For identity management, Blade relays on smart contracts, which implement an Ethereum-based registry. This allows users to create and manage their identities in a self-sovereign manner without the need of a central entity. This way, Blade builds a decentralized service ecosystem that supports developers of decentralized applications and services.
S. Rodriguez Garzon, H. Yildiz and A. Küpper, Towards Decentralized Identity Management in Multi-stakeholder 6G Networks, 2022.

Trust-building mechanisms among network entities of different administrative domains will gain significant importance in 6G because a future mobile network will be operated cooperatively by a variety of different stakeholders rather than by a single mobile network operator. The use of trusted third party issued certificates for initial trust establishment in multi-stakeholder 6G networks is only advisable to a limited extent, as trusted third parties not only represent single point of failures or attacks, but they also cannot guarantee global independence due to national legislation and regulatory or political influence. This article proposes to decentralize identity management in 6G networks in order to enable secure mutual authentication between network entities of different trust domains without relying on a trusted third party and to empower network entities with the ability to shape and strengthen cross-domain trust relationships by the exchange of verifiable credentials. A reference model for decentralized identity management in 6G is given as an initial guide for the fundamental design of a common identity management system whose operation and governance is distributed equally across multiple trust domains of interconnected and multi-stakeholder 6G ecosystems.
S. Rodriguez Garzon, H. Yildiz and A. Küpper, Decentralized Identifiers and Self-sovereign Identity in 6G, 2022.

One of the key challenges for mobile network operators in the future will be to bring together a wide range of new players in the mobile network market under a common umbrella and to orchestrate their innovative technologies to provide economically viable and seamless mobile connectivity to the mobile subscribers. With each new player, be it a cloud, edge or hardware provider, the need for interfaces with secure authentication and authorization mechanisms increases, as does the complexity and operational costs of the public key infrastructures required for the associated identity and key management. While today's centralized public key infrastructures have proven themselves to be technically feasible in confined and trusted spaces, they do not provide the required security once centralized identity providers must be avoided, e.g., because of limited cross-domain interoperability or national data protection legislation, and state-dependent certification authorities can't be commonly trusted, e.g., because of geopolitical reasons. Recent decentralized identity management concepts, such as the W3C proposed recommendation of Decentralized Identifiers, provide a secure, tamper-proof, and cross-domain identity management alternative for future multitenancy 6G networks without relying on identity provider or certification authorities. This article introduces the concept of Decentralized Identifiers together with the principles of Self-sovereign Identity and discusses opportunities and potential benefits of their application and usage for cross-actor and privacy-preserving identity and key management in the next mobile network generation 6G.
M. Westerkamp and A. Küpper, "SmartSync: Cross-Blockchain Smart Contract Interaction and Synchronization" in Proceedings of the IEEE International Conference on Blockchain and Cryptocurrency (ICBC 2022), IEEE, 2022. pp. 1-9.

Cross-Blockchain communication has gained traction due to the increasing fragmentation of blockchain networks and scalability solutions such as side-chaining and sharding. With SmartSync, we propose a novel concept for cross-blockchain smart contract interactions that creates client contracts on arbitrary blockchain networks supporting the same execution environment. Client contracts mirror the logic and state of the original instance and enable seamless on-chain function executions providing recent states. Synchronized contracts supply instant read-only function calls to other applications hosted on the target blockchain. Hereby, current limitations in cross-chain communication are alleviated and new forms of contract interactions are enabled. State updates are transmitted in a verifiable manner using Merkle proofs and do not require trusted intermediaries. To permit lightweight synchronizations, we introduce transition confirmations that facilitate the application of verifiable state transitions without re-executing transactions of the source blockchain. We prove the concept's soundness by providing a prototypical implementation that enables smart contract forks, state synchronizations, and on-chain validation on EVM-compatible blockchains. Our evaluation demonstrates SmartSync's applicability for presented use cases providing access to recent states to third-party contracts on the target blockchain. Execution costs scale sub-linearly with the number of value updates and depend on the depth and index of corresponding Merkle proofs.


F. Victor, P. Ruppel and A. Küpper, "A Taxonomy for Distributed Ledger Analytics" , Computer, vol. 54, no. 02, pp. 30-38, 2021. IEEE Computer Society.

Over the past decade, blockchains and distributed ledger technologies have rapidly evolved. With increasing transaction volumes and the proliferation of decentralized applications based on smart contracts, a need for a deeper understanding arises. We structure the field that we term distributed ledger analytics.

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