## 4 Results: Proof of Concept
### Identity Management Implementation
#### 4.1.3 Verifiable Presentations (VPs)
### Design Artifacts and Stakeholder Evaluation

The proposed framework follows Design Science Research (DSR) principles and incorporates essential artifacts to address the challenges of decentralized identity management in IoT ecosystems. The framework constructs include Decentralized Identifiers (DIDs) and Verifiable Credentials (VCs) that adhere to W3C standards to ensure interoperability and secure identity management. The Tangle, a Directed Acyclic Graph (DAG)-based framework, serves as the backbone for registering and validating these identity constructs in a scalable and decentralized manner. The framework's models integrate key interaction protocols and security mechanisms. For example, IOTA Streams enables secure communication channels with strict access control, ensuring confidentiality and integrity of exchanged data. Key management is handled by IOTA Stranghold, which provides a robust solution for generating, storing, and protecting cryptographic material. The identity validation workflow includes the processesof registering DIDs, issuing VCs, and verifying identities, ensuring that the framework meets the trust requirements of IoT environments. Methodologically, the framework supports autonomous DID registration by IoT devices, eliminating the need for centralized authorities. Trusted entities issue VCs containing critical device attributes, which are securely stored on the Tangle for public verification. Secure data transmission is achieved through encryption mechanisms provided by IOTA Streams, ensuring that only authorized entities can access sensitive information. The framework was instantiated through a proof-of-concept implementation on a Raspberry Pi 4, demonstrating its feasibility in resource-constrained environments. The device successfully performed critical tasks, including DID creation, VC issuance, and real-time communication with other nodes in the Tangle. The evaluation of the proposed framework considered key stakeholders such as IoT device manufacturers, service providers, and end users. For device manufacturers, the framework addresses the need for secure and unique device identities through the use of DIDs and VCs, eliminating reliance on external certification authorities. Service providers benefit from the Tangle's scalability and feeless transactions, which reduce operational costs and support real-time verification of large-scale IoT networks. For end users, the framework increases trust by enabling them to independently verify device credentials, in line with Web 3.0 principles of decentralization and user empowerment. Measurement results from the proof-of-concept implementation demonstrated the viability of the framework. The Raspberry Pi showed acceptable latency for cryptographic operations, indicating that the system is feasible even for low-power devices. The scalability of the Tangle allows the framework to meet the needs of large IoT ecosystems while providing robust security through encrypted communication and secure key management. In addition, the framework empowers end users by providing independent verification capabilities, reinforcing its alignment with user-centric design principles. While the framework shows promising results, several areas remain for future exploration. Optimizing cryptographic algorithms for resource-constrained devices, integrating advanced communication protocols such as DIDComm, and expanding evaluation scenarios to different IoT use cases could further improve the system's performance and applicability. ## 5 Discussion

The results of our study underscore the potential of decentralized identity management systems, particularly those leveraging IOTA's Tangle technology, to address the critical challenges associated with IoT ecosystems. The implementation of Decentralized Identifiers (DIDs) and Verifiable Credentials (VCs) within the IOTA framework demonstrates significant progress in improving the security, scalability, and privacy of IoT devices.