A ledger is a file that is constantly growing. It keeps a permanent record of all the transactions that have taken place between two parties on the blockchain network.

There are three common types of a ledger that can be considered by users in the blockchain:

Centralized Network
Decentralized Network
Distributed Network

In the context of blockchain, a ledger refers to a decentralized and distributed database that records all transactions across a network of computers. It serves as a tamper-resistant and transparent record of all transactions in a blockchain network.

Common types of ledgers in blockchain include:

Distributed Ledger: This is the overarching term for a ledger that is spread across multiple nodes (computers) in a network. Each node maintains a copy of the entire ledger, and consensus mechanisms are employed to agree on the state of the ledger.
Public Ledger: This type of ledger is open to anyone in the network. All participants have access to the entire transaction history, ensuring transparency.
Private Ledger: This ledger is restricted to a specific group of participants. Access to the ledger is limited to authorized users, providing a level of privacy.
Permissioned Ledger: Similar to a private ledger, a permissioned ledger restricts access to authorized participants. However, permissioned ledgers may have different levels of access, granting certain permissions to some users while restricting others.
Smart Contract Ledger: Some ledgers, such as Ethereum, support the execution of smart contracts. Smart contracts are self-executing contracts with the terms of the agreement directly written into code. The ledger records the execution and outcomes of these contracts.

Understanding these ledger types is essential for users in the blockchain space, as it helps them choose the appropriate platform based on their specific needs and requirements.