I'm soo deep inside the consensus protocols like PoW, PoS, PoA or other variants used on permissioned/private blockchains such as JPMorgan's Quorum (Based on Raft), Istambul etc..

But I've not entered yet on the Hyperledger consensus protocols and it's implementations specifications and differences.

So my questions are:

  • What is the consensus protocol used on Hyperledger? It's inherited from any of the mentioned above?
  • Which are the main differences between it's variants (Fabric, Iroha, Sawtooth, and Indy)?

Please, it'll be fantastic if useful documentation links/articles/lectures were added with the answers.


  • 1
    Might be considered off-topic if it's not specifically about Hyperledger Burrow (which uses a licenced EVM). The Bitcoin Stack Exchange board is still the best place for general blockchain questions. (See: ethereum.meta.stackexchange.com/questions/555/…) May 26 '18 at 15:39
  • Well.. gess that i'll have to ask there.. At least would you answer just for the Burrow part?
    – CPereez19
    May 26 '18 at 15:45
  • Yes :-) Sorry, didn't mean to sound like a killjoy. May 26 '18 at 15:55

Keep in mind that Hyperledger is a Linux Foundation consortium and refers to multiple, independent blockchain platforms.

The above is missing the Consensus algorithms from Hyperledger Sawtooth, so here they are:

  • PoET Proof of Elapsed Time (optional Nakamoto-style consensus algorithm used for Sawtooth). PoET with SGX has BFT. PoET Simulator has CFT. Not CPU-intensive as with PoW-style algorithms, although it still can fork and have stale blocks . See PoET specification at https://sawtooth.hyperledger.org/docs/core/release s/latest/architecture/poet.html
  • RAFT Consensus algorithm that elects a leader for a term of arbitrary time. Leader replaced if it times-out. Raft is faster than PoET, but is not BFT (Raft is CFT). Also Raft does not fork. Hyperledger Sawtooth has the advantage of having Unpluggable Consensus. An algorithm can be changed without reinitializing the blockchain or even restarting the software.

Here are some other consensus algorithms:

  • PoW Proof of Work. Completing work (CPU-intensive Nakamoto-style consensus algorithm). Usually used in permissionless blockchains
  • PoS Proof of Stake. Nakamoto-style consensus algorithm based on the most wealth or age (stake)
  • PBFT Practical Byzantine Fault Tolerance. A "classical" consensus algorithm that uses a state machine. Uses leader and block election. PBFT is a three-phase, network-intensive algorithm (n^2 messages), so is not scalable to large networks

Confining the question to Hyperledger Burrow1 - which uses an Apache-licensed implementation of the EVM - the default consensus engine is Tendermint (site; white paper).

From the docs:

Transactions are ordered and finalised with the Byzantine fault-tolerant Tendermint protocol. The Tendermint protocol provides high transaction throughput over a set of known validators and prevents the blockchain from forking.

1 As per previous discussions, the general Hyperledger Fabric framework and associated projects which don't implement any part of the EVM, or anything else related to Ethereum, are probably off-topic. Unfortunately the Blockchain Technology SE site didn't get enough backing during its Area51 phase, so the best place for questions like this is probably still the Bitcoin SE site.

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