A simple scheme to understand the blockchain
Many of the meanings of the blockchain are inside its literal meaning: block chain.
The blockchain is an accounting book, a ledger, of records organized in “blocks” that are linked to each other by cryptographic validation. Imagine any register, where in order to consult a data item, you need to read many, many, endless books.
It is a digital memory of the truth
The key to reading this “ledger” is not stored in a centralized place or managed by a single entity, but is distributed among “innumerable” subjects.
A block validation system allows you to add new transactions that can not be altered in any way by any subject: it is not possible to change the content, it is impossible to change the data, it is impossible to change the subjects involved.
An indelible and unchangeable writing
In the ledger, new and old transactions will coexist, characterized by extreme transparency and resilience (in IT world resilience is the ability of a system to adapt to the conditions of use and to resist usury in order to guarantee the availability of the services provided)
Open source softwares that uses blockchain technology are called Dapps.
At the base of the generation of a “data” on the ledger, there is clearly the carrying out of a transaction that can be compared to a fee (it is the best known use case for the so-called Bitcoin and therefore for any transaction under onerous) but also free if it involves the generation of a “data” of another nature (eg an individual’s birth certificate).
The transaction, as defined above, therefore needs a validation and in this process intervene those defined ‘nodes’: Computers connected in P2P (peer to peer) network which, through an algorithm, they will evaluate the transaction and for this function, rewarded, through a system of reward, with the cryptocurrency (criptocurrency) underlying the system.
Once the transaction has been verified, it is combined with other transactions in order to create a “block of data to be transcribed” on the ledger.
Afterwards, this block will be combined with the existing blockchain and so the “transaction” will be finally completed