In order to understand blockchain, in this context it is gradual to consider how bitcoin implemented it. Like a database, a bitcoin requires a set of computers to store its blockchain. For Bitcoin, this blockchain is just a special kind of database that performs every bitcoin transaction. In the case of Wikipedia, and unlike most databases, these computers are not under one roof, and each computer or group of computers is controlled by a unique person or group of people.
Imagine that a company has a server of 10,000 computers with a database containing all the information about its user account. The company has a warehouse in which all these computers are located under one roof and it has complete control over each of these computers and all the information contained in it. Similarly, a bitcoin consists of thousands of computers, but each computer or a group of computers that stores its blockchain is in a different geographical location, and they are all run by individuals or groups of individuals. These computers that make up bitcoin networks are called nodes.
In this model, the bitcoin blockchain is used in a decentralized manner. However, the private centralized blockchain, in which the computers that make up its network, are owned and operated by a single entity.
In blockchain, each node contains a complete record of the data that has been stored in the blockchain since its inception. For bitcoins, the data is the entire history of all bitcoin transactions. If a code has a data error, it can use thousands of other nodes as checkpoints to correct itself. That way, no node on the network can change the information it contains. Because of this, the transaction history in each block that makes up the bitcoin chain is irreversible.
If a user interferes with the bitcoin transaction record, all other nodes refer to each other and it is easy to identify the node with incorrect information. This system helps to establish an accurate and transparent sequence of events. For Bitcoin, this information is a list of transactions, but it is also possible that Blockchain may store various information, such as legal contracts, government identities, or inventory of a company’s products.
In order to change the way this system works or the information contained in it, most of the computing power of the decentralized network will have to rearrange these changes. This ensures that whatever changes take place are in the interest of the majority.