Blockchain networks can generally be divided into two main categories: permissioned and permissionless blockchains. The fundamental distinction between these two lies in the level of access control and participation within the network.

Permissioned Blockchains

A permissioned blockchain is a network where access and participation are controlled. To join, you must have permission or approval from a governing authority or administrator. In this setup, only selected participants can validate transactions and participate in the consensus process.

• Controlled Access: Participants need authorization to join the network.
• Participation Restrictions: Not all users have the same privileges; roles like validators or transaction initiators are predefined.
• Privacy and Security: Since participation is limited, permissioned blockchains can offer a higher degree of privacy and security, making them attractive for use in industries like finance or supply chain management.

An example of a permissioned blockchain is Hyperledger, a platform commonly used by enterprises to create private and secure blockchain solutions.

Permissionless Blockchains

In contrast, permissionless blockchains are open and decentralized, allowing anyone to join, validate transactions, and participate in the network without needing any special permission. These blockchains are like public spaces, where anyone can enter and contribute.

• Open Access: Anyone can join, read, and write data to the blockchain.
• Decentralization: No central authority controls the network, and anyone can take part in validating transactions and securing the blockchain.
• Transparency: Since the network is open to all, every transaction and activity on the blockchain is visible to the public.

Bitcoin and Ethereum are popular examples of permissionless blockchains, where users can freely participate in mining or staking without requiring approval from any central authority.

Key Differences

• Access: Permissioned blockchains require authorization to join, while permissionless blockchains are open to everyone.
• Governance: In permissioned blockchains, a central authority governs the network, whereas in permissionless blockchains, governance is decentralized.
• Use Cases: Permissioned blockchains are ideal for industries requiring control and privacy, while permissionless blockchains are used in scenarios that benefit from decentralization and openness, like public cryptocurrencies.