Blockchain Distributed ledger
A distributed ledger is a type of database that is consensually shared, replicated, and synchronized among the members of a decentralized network. All the information on this ledger is securely and accurately stored using cryptography. This information can be accessed using keys and cryptographic signatures. The distributed ledger allows transactions to have public "witnesses," which makes cyberattack more difficult. It records the transactions such as the exchange of assets or data, among the participants in the network.
All the participants in the network govern and agreed upon consensus on the updates to the records in the ledger. There is no central authority, or third-party mediators such as a financial institution or government agencies are involved. Every record in the distributed ledger has a timestamp and unique cryptographic signature. This makes the ledger an auditable, immutable history of all transactions in the network.
Further, if any alterations made to the ledger, they are reflected and copied to all participants in a matter of seconds or minutes. In other words, when any alterations or updates happen in the ledger, each node constructs the new transaction, and then the nodes vote by consensus algorithm on which copy is correct. Once a consensus algorithm has been determined, all the other nodes update themselves with the new and correct copy of the ledger.
The primary advantage of the distributed ledger is the lack of central authority. As we know that centralized ledgers are prone to cyber-attack, distributed ledgers are inherently very harder to attack. It is because all the distributed copies need to be attacked simultaneously for an attack to be successful.