A blockchain is a decentralized communication and information backup system. What does this mean?

To understand, it will be easier for us to compare the blockchain to a smart book. This book is copied in different identical copies. There are several similar versions of this book to prevent that if a book is hacked, the entire history of information is tampered with. We consider that if there is a book that is inconsistent with the others, it is false. To hack a blockchain, one must therefore be able to instantly modify more than 50 percent of pounds consistently. Very complex, which makes blockchains very secure tools.

What does it look like? Imagine that in our book, the first word on the first page represents the first transaction. The last word on the last page represents the last transaction. If you read a book from beginning to end, you know all the transactions that have taken place in history.
If someone makes a transfer, just go back to the book to see if the person making the transfer has the funds. If it has the cryptocurrency, we verify that the account to which the transfer is to arrive is indeed existing. If this is the case, the transfer is made.

The book is copied to thousands of different computers and servers making this system very secure. Blockchains are not only useful for cryptocurrencies, have imagined that they are also used in the industrial, transportation, security, etc.