The emblematic example is Bitcoin. In the case of cryptocurrency, each block contains a certain number of transactions and is connected to another through a peer-to-peer network, which in turn connects to a validation protocol for each new block added to the chain. Each node (i.e., a computer connected to the network) receives a copy of the blockchain, which is downloaded automatically.

In the blockchain concatenation, each new block consists of a group of the most recent transactions, which are recorded and added in chronological order. This allows market operators to track digital currency transactions without the need for a central register.

Each block, therefore, contains a pointer linking it to the previous block and shares the ledger of all information validated by the system. What makes blockchain technology so secure is that the data in a block cannot be retroactively altered without changing all subsequent blocks, which would require the majority consensus of the network. Thus, since blockchain technology is based on an open and distributed digital ledger of transactions, based on the consensus among network participants, the system becomes incorruptible unless the entire network is compromised.

Blockchain can offer highly innovative solutions in creating a revolutionary traceability system capable of establishing a quantitative and qualitative model for information shared along the food supply chain. This potential puts blockchain at the service of the supply chain, providing new tools to ensure the best food traceability, aiming to achieve new levels of food security and safety.

Applied under a new concept of trust, blockchain is relevant to the food supply chain—particularly the fishing supply chain. The fish supply chain, already heavily affected by illegal activities, has areas of opacity that fail to guarantee producers, retailers, and consumers the quality and reliability of all steps involved. In other words, the real issue is establishing a situation of trust that provides clear guarantees to all stakeholders about not only the quality of the work performed but also adherence to rules and rights of all businesses and individuals directly and indirectly involved in this supply chain.

It is precisely on the issue of trust that the blockchain-based solution developed by the project partners and collaborators is focused. Specifically, MTM, in collaboration with the Department of Engineering (DI) at the University of Palermo and the Reggio Calabria branch of the Institute of Clinical Physiology (IFC) of the CNR, has developed a blockchain-based traceability system. This system certifies the entire production chain, ensuring both product quality and consumer safety. The block validation mechanism based on mining, which underlies blockchain technology, guarantees the authenticity and immutability of the data stored in a distributed ledger through a cryptographic hash function. The immutability of this shared and distributed digital ledger is ensured by the fact that each block in the chain contains the unique hash code of the previous chain, meaning that it is impossible to alter any block without changing the entire chain.

Finally, blockchain does not require any external or internal trusted authority to guarantee the integrity and authenticity of the data. The system itself acts as a guarantor, as it is impossible for anyone to alter the information in the chain. This is because the data is not stored by a single entity but replicated across an entire network of computers. Ultimately, the value of blockchain technology lies in the distributed security of the system.