A blockchain is essentially a digital ledger of transactions that is replicated and distributed across a network of computer systems across the blockchain. Each block in the chain contains a series of transactions, and each time a new transaction occurs in the blockchain a record of that transaction is added to each participant's ledger. Decentralized database managed by multiple participants is known as Distributed Ledger Technology (DLT).
In Blockchain, if a block in a chain is changed, it is instantly understood that it has been changed because all information is transparent. If hackers want to disrupt a blockchain system, they will have to modify every block in the chain across all distributed versions of the chain. This is close to impossible.
Blockchains such as Bitcoin and Ethereum are constantly growing as each transaction is added to the chain and the new transaction is added to the previous transaction, significantly increasing the security of the ledger.
Is Blockchain Safe?
There have been many attempts to create digital currency in the past, but they always failed.
It's all a matter of trust. If someone creates a new currency called X dollars, how can we trust that they won't give themselves a million X dollars or steal your X dollars for themselves?
Bitcoin is designed to solve this problem using a specific type of database with blcokhain. Blockchain is different because no one is responsible; It is managed by the people who use it. Moreover, bitcoin cannot be counterfeited, hacked, or spent multiple times. That's why people who have this money cannot attempt such a thing because everything in the blockchain is open and cannot be hidden. In short, they cannot transfer, multiply or destroy the coins they hold unregistered.