Difference between Public and Private blockchain

1. What is Pubic Blockchain ?
Public blockchains are open networks that allow anyone to participate in the network i.e. public blockchain is permissionless. In this type of blockchain anyone can join the network and read, write, or participate within the blockchain. A public blockchain is decentralized and does not have a single entity which controls the network. Data on a public blockchain are secure as it is not possible to modify or alter data once they have been validated on the blockchain.

Some features of public blockchain are :

  • High Security –
    It is secure Due to Mining (51% rule).
  • Open Environment –
    The public blockchain is open for all.
  • Anonymous Nature –
    In public blockchain every one is anonymous. There is no need to use your real name, or real identity, therefore everything would stay hidden, and no one can track you based on that.
  • No Regulations –
    Public blockchain doesn’t have any regulations that the nodes have to follow. So, there is no limit to how one can use this platform for their betterment
  • Full Transparency –
    Public blockchain allow you to see the ledger anytime you want. There is no scope for any corruption or any discrepancies and everyone has to maintain the ledger and participate in consensus.
  • True Decentralization –
    In this type of blockchain, there isn’t a centralized entity. Thus, the responsibility of maintaining the network is solely on the nodes. They are updating the ledger, and it promotes fairness with help from a consensus algorithm .
  • Full User Empowerment –
    Typically, in any network user has to follow a lot of rules and regulations. In many cases, the rules might not even be a fair one. But not in public blockchain networks. Here, all of the users are empowered as there is no central authority to look over their every move.
  • Immutable –
    When something is written to the blockchain, it can not be changed.
  • Distributed –
    The database is not centralized like in a client-server approach, and all nodes in the blockchain participate in the transaction validation.

2. What is Private Blockchain ?
A private blockchain is managed by a network administrator and participants need consent to join the network i.e., a private blockchain is a permissioned blockchain. There are one or more entities which control the network and this leads to reliance on third-parties to transact. In this type of blockchain only entity participating in the transaction have knowledge about the transaction performed whereas others will not able to access it i.e. transactions are private.

Some of the features of private blockchain are :

  • Full Privacy –
    It focus on privacy concerns.
  • Private Blockchain are more centralized.
  • High Efficiency and Faster Transactions –
    When you distribute the nodes locally, but also have much less nodes to participate in the ledger, the performance is faster.
  • Better Scalability –
    Being able to add nodes and services on demand can provide a great advantage to the enterprise.



Difference between Public and Private blockchain :

S.no Basis of Comparison Public BlockChain Private BlockChain
1. Access – In this type of blockchain anyone can read, write and participate in a blockchain. Hence, it is permssionless blockchain. It is public to everyone. In this type of blockchain read and write is done upon invitation, hence it is a permissioned blockchain.
2. Network Actors – Don’t know each other Know each other
3. Decentralized Vs Centralized – A public blockchain is decentralized. A private blockchain is more centralized.
4. Order Of Magnitude – The order of magnitude of a public blockchain is lesser than that of a private blockchain as it is lighter and provides transactional throughput. The order of magnitude is more as compared to the public blockchain.
5. Native Token – Yes Not necessary
6. Speed – Slow Fast
7. Transactions pre second – Transactions per second are lesser in a public blockchain. Transaction per second is more as compared to public blockchain.
8. Security – A public network is more secure due to decentralization and active participation. Due to the higher number of nodes in the network, it is nearly impossible for ‘bad actors’ to attack the system and gain control over the consensus network. A private blockchain is more prone to hacks, risks, and data breaches/ manipulation. It is easy for bad actors to endanger the entire network. Hence, it is less secure.
9. Energy Consumption – A public blockchain consumes more energy than a private blockchain as it requires a significant amount of electrical resources to function and achieve network consensus. Private blockchains consume a lot less energy and power.
10. Consensus algorithms – Some are proof of work, proof of stake, proof of burn, proof of space etc. Proof of Elapsed Time (PoET), Raft, and Istanbul BFT can be used only in case of private blockchains.
11. Attacks – In a public blockchain, no one knows who each validator is and this increases the risk of potential collision or a 51% attack (a group of miners which control more than 50% of the network’s computing power.). In a private blockchain, there is no chance of minor collision. Each validator is known and they have the suitable credentials to be a part of the network.
12. Effects – Potential to disrupt current business models through disintermediation. There is lower infrastructure cost. No need to maintain servers or system admins radically. Hence reducing the cost of creating and running decentralized application (dApps). Reduces transaction cost and data redundancies and replace legacy systems, simplifying documents handling and getting rid of semi manual compliance mechanisms.
13. Examples – Bitcoin, Ethereum, Monero, Zcash, Dash, Litecoin, Stellar, Steemit etc. R3 (Banks), EWF (Energy), B3i (Insurance), Corda.

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