• blockchain
• extensibility
• hyperledger fabric
• interoperability
• iota
• tradelens

Over the past few years, blockchain technology and similar Distributed Ledger Technologies (DLTs) has been evolving rapidly, resulting in the creation of several, fragmented projects, each attempting to match the market's expectations and its ever-changing requirements. Because there is no control over the creation of new blockchains, anyone knowledgeable with the technology's workings can build their own modified version of an existing solution. Each new blockchain tries to solve a particular use case, or to match certain performance goals. Nevertheless, each solution will still have security issues, have a weak user base, and find itself with uncaught flaws and bugs. Companies and researchers started to address the issues of DLT interoperability, in a way that is similar to the work done to prevent cloud providers lock-in. Certain applications making extensive use of blockchain technology, especially critical ones that require seamless dependability, necessitate of interoperability mechanisms (IMs) that help them achieve independence and avoid falling into the data and value silos of DLT. The interoperability solutions currently available for blockchains are many and heterogeneous, hence, it is important to be able to evaluate these IMs with two purposes: discern between different types of solutions picking the most appropriate, and have a standard way to compare a proprietary solution against already existing ones.
The goal of the thesis is twofold. On one side, the frameworks and tools available in the literature to evaluate IMs are studied to select the most complete and appropriate, also proposing an extension based on the knowledge acquired during the research phase. On the other side, the thesis proposes the evaluation of a real IM called InteroperaChain, using the presented framework. Based on the issues emerged from the evaluation, I proposed and implemented targeted structural changes to the mechanism with the goal of improving its evaluation score. A final re-assessment showed that the actions successfully yielded a better result, in particular for what concerned the data model and extensibility sections of the framework. The results indicate that using the evaluation framework against an interoperability solution can help to take targeted actions to improve its quality and efficacy.