The term Blockchain refers to a shared data structure used in computer science, consisting of information packets called "blocks" whose integrity is guaranteed by consensus mechanisms using cryptographic techniques. In other words, the Blockchain manages and updates a register of data and information (such as transactions) in a unique and secure way, using the features of a network of computer nodes, openly, shared and distributed. Its characteristics are:

• - Decentralization: there is no central control and verification entity
• - Security: the information is shared and usable by everyone, so it is necessary to obtain consensus from all network members for an asset to be recognized. The goal is to empower new technologies, making the process more efficient and transparent.
• - Certification: certification is safer with Blockchain because it is not replicable or modifiable, making it authentic.
• - Immutability: it is almost impossible to modify information without the consent of all members with access to the network.

Therefore, a blockchain can ensure that data is stored and immutable, and that a certain action (such as a payment) is executed in a verifiable way by everyone without fraud. There are different types of blockchain networks:

• - Public blockchain networks: everyone can access the network, but there are some disadvantages such as low security and lack of privacy, as in the case of Bitcoin.
• - Private blockchain networks: unlike the previous type, it has an administrator who controls users, decides participants, and manages the shared register.
  
• - Authorized blockchain networks: they have restrictions for participants who are only authorized for certain activities.
  
• - Blockchain consortia: different organizations are responsible for a blockchain.

The Blockchain technology, originally used as a solution to create a payment system without intermediaries (see Bitcoin), is now finding more and more applications in various sectors that use it, for automation, reliability, and streamlining of processes. It can be used for traceability of food products, in the real estate market to streamline the process of buying/selling a property, or in healthcare to make patient data more secure.