PoW is a mechanism to keep block chain incorruptable from malicious nodes. Now in a private block chain where all nodes are supposed to be honest, what purpose PoW would serve? Would it not be just a waste of computational power?

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    What do you try to achieve from having a blockchain? Oct 23, 2017 at 8:11
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    Why using blockchain if all the nodes are supposed to be honest ? Oct 23, 2017 at 8:22
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    @AdrienForbu to agree on the state, if 5 companies are honest but they want to share a db, blockchain might be a good solution. of course without PoW. I know it's not where the blockchain shines but still a valid use-case imo. Honest != never make mistakes, blockchain makes sure there is global ordering of transactions and there is only 1 state they all agree.
    – EralpB
    Nov 23, 2017 at 11:55

3 Answers 3


You might want to look at this article.

To resume some of the points :

  • A private blockchain is a form of shared database
  • Different consensus protocols than Proof Of Work exist for private/permission blockchains
  • Check out Quorum and Hyperledger Fabric for enterprise blockchain solutions under active development

Proof of work is not required on a permissioned or private blockchain.

For the more efficient operation, for example Proof-of-Authority can be used, like in Ethereum Kovan testnet.


In general, PoW is immoral in it's waste of energy. Other consensus algorithms are available that do are more energy efficient, such as

  • PoS (Proof of Stake) used by Ethereum (winner has the most "stake" or "wealth" of some kind)
  • PBFT (Practical Byzantine Fault Tolerance) elects a leader. Does not scale due to the high number of messages between nodes.
  • Raft (which elects a leader until the leader times-out). Scales well and is efficient. Not BFT (vulnerable to bad actor nodes)
  • PoET (Proof of Elapsed Time) (which generates a random wait time and the first timer to expire wins)
  • PoS is not used by Ethereum at the moment, they have plans to upgrade in the near future though
    – abed
    Nov 8, 2018 at 9:11

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