## 2 Maritime Digitalization  
The maritime sector is undergoing a significant transformation and digitalization process with advanced Information and Communication Technologies (ICT) technologies [18; 19; 20]. This digitalization process is reshaping traditional maritime operations to be more efficient, transparent, and sustainable. With the development of technologies such as the Internet of Things (IoT), big data analytics, blockchain, and artificial intelligence (AI), the maritime sector is moving towards becoming more interconnected. These advancements enable the real-time monitoring of vessels, predictive maintenance, and optimized route planning, which reduce fuel consumption and operational costs, etc. Digital platforms facilitate better coordination among stakeholders, enhance supply chain visibility, and improve the overall safety and security of maritime operations, addressing the growing demands for efficiency and sustainability in global trade and logistics, ultimately positioning the sector to meet future challenges with greater agility and resilience [18; 19; 20]. It has been well-accepted that Artificial Intelligence (AI) and blockchain have become two of the most trending and disruptive technologies nowadays that may fundamentally reshape how the way we live, work and interact with the world [21]. The recent resurgence in AI is driven by breakthroughs in deep learning technologies and is fueled by the significant digital data available from the smart systems of various businesses (relying on sensing and IoT devices), social media, web applications [22], etc. AI-powered solutions are reshaping maritime operations in many areas, such as optimizing vessel scheduling, route planning, predictive maintenance, etc. AI-driven solutions help port authorities and shipping companies manage and predict traffic flow, reduce waiting times, and improve cargo handling efficiency. In the context of autonomous ships, AI is integral to achieving real-time situational awareness, risk detection, and collision avoidance, which are critical for ensuring vessel safety and compliance with regulations. These applications benefit from advancements in learning-based technologies, which leverage vast amounts of data from vessel movements, onboard equipment sensing, port operations and environment patterns. Blockchain technology can manage a shared ledger of data, transactions, and logs in a decentralized, secure, and trusted manner, which can encourage collective data usage because it provides transparency, traceability and auditability regarding whose data is accessed, how the data are used, when, and by whom. Blockchain technology, rooted in the studies on cryptographically secured chains of blocks [23], was first applied and became popular for the digital currency network Bitcoin, launched in 2008 [24]. As the underlying decentralized data structure, blockchain is distinguished by its core characteristics of immutability, transparency and security, which ensures the integrity and reliability of the information stored on the blockchain, fostering trust in the system. In addition to its great success in the finance sector, the transformative potential of blockchain is evident across numerous sectors, where it promises enhanced traceability and audibility, operational efficiency, and security, especially in collaborative cross-organizational processes [25; 26]. Blockchain can be categorized into public, private, and consortium networks. Public blockchains are fully decentralized and permissionless without a central authority, thereby allowing anyone to set up nodes and access the blockchain networks [27]. In the early stages of blockchain, a notable drawback of the public chain was its low transaction per second (TPS) performance, as it had to undergo a proof-of-work (PoW) consensus [28]. Nowadays, Layer 1 and Layer 2 scaling solutions [29] have been proposed for public chain networks to enhance the TPS performance.