1. Public Blockchains

• Definition: Open, permissionless networks where anyone can join, read, and write transactions.

• Examples: Bitcoin, Ethereum, Sui, Solana.

• Characteristics:

  • Decentralized and censorship-resistant.
  • Uses consensus mechanisms like Proof of Work (PoW) or Proof of Stake (PoS).
  • Transparent—anyone can audit the ledger.
  • Typically slower and more resource-intensive due to large validator sets.

• Best for: Cryptocurrencies, DeFi, NFTs, and open applications requiring maximum trustlessness.

2. Private Blockchains

• Definition: Permissioned networks where a single organization controls participation and governance.

• Examples: Hyperledger Fabric (IBM), R3 Corda.

• Characteristics:

  • Access restricted to approved participants.
  • Higher speed and efficiency since validator sets are small.
  • Centralized governance reduces trustlessness but improves compliance and privacy.
  • Not as resilient to censorship or tampering compared to public blockchains.

• Best for: Enterprises, supply chain management, healthcare, and internal data sharing.

3. Consortium (Federated) Blockchains

• Definition: Semi-decentralized networks controlled by a group of organizations instead of a single entity.

• Examples: Quorum, Energy Web Chain.

• Characteristics:

  • Governance shared among multiple institutions.
  • Faster than public blockchains, more trustless than private blockchains.
  • Good balance between decentralization and efficiency.
  • Requires coordination between members for consensus and updates.

• Best for: Banking consortia, trade finance, interbank payments, cross-company data sharing.

4. Hybrid Blockchains

• Definition: Combines features of both public and private blockchains. Certain data is private, while other parts are public.

• Examples: Dragonchain, IBM Blockchain solutions.

• Characteristics:

  • Offers selective transparency—some data public, sensitive data private.
  • Controlled access with the ability to leverage public chain verification.
  • Flexible governance, but more complex to implement.

• Best for: Government services, enterprise collaboration with public verification, healthcare records.

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