The continual increase in cyber crime revolving blockchain applications calls for secure blockchain systems and clarity on the division of security responsibilities. This research is an integrated project between two master programmes at the Delft University of Technology: Computer Science and Communication Design for Innovation, and focuses on software testing and security responsibilities.

In this study, we investigate if grammar-based fuzzing, a popular approach for identifying bugs in software, is effective on JSON-RPC systems like blockchain applications Ripple and Ethereum. Furthermore, we evaluate whether we can improve upon traditional grammar-based fuzzing by using evolutionary search.
We introduce GEFRA, a black-box grammar-based fuzzing tool that generates tests for JSON-RPC APIs.
Using a diversity-based fitness function that leverages system feedback, GEFRA is able to effectively guide the search process towards new test cases that obtain additional test coverage.

Additionally, various perspectives on blockchain security responsibilities are investigated. A media content analysis was performed and interviews were conducted with legal and blockchain experts.
News media frequently frame end users as responsible for the prevention of blockchain attacks. While attackers are legally responsible, users are left to deal with the consequences if attackers cannot be found. Responsibilities generally end up with users as decentralisation is the core idea of blockchain. Legislation may be the only solution to define a clear division of responsibilities.

Escape rooms are multi-player games that contain several puzzles that need to be solved in order to open locked chests and discover new clues, which eventually enables the players to escape the room. While the players are inside the escape room, the game host observes the group through live cameras. When players tend to fail to make it out of the escape room in time, the host needs to give them hints to keep them on track. Popup-escape is a company that designs escape rooms. They have asked us to develop an application that supports the game host in the process of observing escape rooms. Hence, we developed an application that displays live video streams and shows valuable information about the progress of the game. The game host can configure the escape room in the application before players enter the escape room. This configuration sets up how the escape room is structured. The game host indicates the number of chests (key points in the game) that need to be unlocked and the time it should take players to open it. The application then processes the incoming video streams and detects chests that have been opened, as well as the level of current activity. The progress is measured against time. When the progress made is falling short compared to the preconfigured time limits, the host gets a warning, alerting him that the players in the escape room need a hint in order to be able to finish the game in time.