## 4 Results: Proof of Concept
### Identity Management Implementation
#### 4.1.3 Verifiable Presentations (VPs)
IOTA enhances security and privacy by leveraging its decentralized and tamper-proof structure, eliminating single points of failure. Each transaction is independently validated by multiple nodes, ensuring resilience against attacks. This is in contrast to Ethereum, which relies on miners and a proof-of-work system, and Hyperledger Indy, which uses a permissioned blockchain model. In addition, IOTA's tools, such as Stronghold for secure key management and Streams for encrypted data exchange, make it well suited for privacy-sensitive IoT applications. These features provide robust protection for device identities and communications [27]. Scalability and Interoperability

The Tangle's scalability is a key strength, as increased network activity results in faster transaction validation, unlike blockchains where congestion can slow performance. This \begin{table}
\begin{tabular}{p{85.4 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Aspect** & **IOTA (Tangle)** & **Blockchain** \\ \hline Architecture & Directed Acyclic Graph (DAG) with inter-connected nodes. & Sequential blocks linked in a linear chain. \\ \hline Transaction Validation & Parallel validation, where each transaction approves two previous transactions. & Sequential validation requiring consensus for each new block. \\ \hline Transaction Costs & Feeless transactions, enabling cost-effective microtransactions. & Transaction fees are required, potentially expensive for frequent operations. \\ \hline Energy Efficiency & Lightweight and energy-efficient; no mining required. & Energy-intensive due to mining (e.g., Proof-of-Work) or staking mechanisms. \\ \hline Scalability & Increases with network activity due to parallel processing. & Limited scalability; bottleneck from block size and sequential validation. \\ \hline Consensus Mechanism & Achieved via cumulative weight of transactions and Markov Chain Monte Carlo (MCMC) algorithm. & Requires miners or validators to achieve consensus (e.g., Proof-of-Work or Proof-of-Stake). \\ \hline Data Storage & Metadata and cryptographic proofs stored on the Tangle; bulk data stored off-chain. & Primarily on-chain, with limited off-chain options for scalability. \\ \hline Suitability for IoT & Optimized for IoT environments; lightweight, scalable, and feeless. & Less suitable for IoT due to high computational and energy demands. \\ \hline Fault Tolerance & Decentralized and resilient; no single point of failure. & Vulnerable to network partitions or attacks on mining pools. \\ \hline Interoperability & Focused on decentralized identities and IoT-specific applications. & Broader application but requires bridges for interoperability. \\ \hline Use Cases & Ideal for identity management in IoT ecosystems, enabling lightweight trust and data validation. & General-purpose identity systems, with additional layers for IoT integration. \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Comparison of the IOTA Tangle and blockchain for decentralized identity management. scalability is essential for IoT ecosystems with millions of connected devices. However, broader interoperability remains a challenge. While IOTA aligns with W3C standards for DIDs and VCs, integration with frameworks such as Hyperledger Indy or Ethereum-based solutions requires bridging mechanisms to ensure seamless interoperability. Addressing this will be a critical area for future development [28]. Energy Efficiency

IOTA's lightweight proof-of-work mechanism, designed solely to prevent spam, is far more energy efficient than traditional blockchains like Ethereum, which rely on energy-intensive mining. For IoT scenarios, where devices often operate on limited power sources, this low energy requirement is a significant advantage. While Hyperledger Indy's permissioned model is also energy-efficient, its blockchain-based architecture does not match the resource optimization provided by Tangle, particularly for IoT workloads [29].