Guides to Blockchain Consensus Protocols

Delegated Byzantine Fault Tolerance (dBFT) Guide

Election System Picture

What is Delegated Byzantine Fault Tolerance (dBFT)?

Delegated Byzantine Fault Tolerance (dBFT) is a consensus protocol that was used and made popular by NEO cryptocurrency and blockchain. It provides its users (token holders) an election system and the rights to vote for speakers and delegates who are responsible for the governance of its blockchain ecosystem.


Prominent Consensus Protocols

There are a number of blockchain consensus protocols operating around the world, each with its own strengths and weaknesses. The most well-known of those are Proof of Work (PoW) currently used by Bitcoin, Proof-of-Stake (PoS) used by DASH or Delegated Proof of Stake (DPoS) used by EOS. For this particular guide, you will be provided a basic understanding on another consensus mechanism known as the Delegated Byzantine Fault Tolerance (dBFT).


A blockchain that is decentralized must be immutable, able to operate via multiple nodes, add authentic data to its records and be governed without compromising its integrity. Hence, the consensus mechanism used by the blockchain network is very important and is the key to accomplish the above requirements.

Election System

As mentioned above, dBFT provides its users an election system to vote for the governance of the ecosystem and network. Each citizens or native token holders (NEO tokens for the case of NEO) can vote and elect delegates as the bookkeeping nodes, although a delegate will need to fulfill the following requirements first before he/she can be chosen:

1. Holds at least 1000 GAS tokens

2. Owns specific equipment

3. Has a dedicated and stable internet connection

A speaker is then chosen randomly from the elected delegates and will be given the job to verify blocks (containing transactions). The speaker will then propose and send new block to all delegates to match with their blocks. The proposed block will be added and recorded to the blockchain if at least 2/3 of the delegates agree that it is valid. If less than 2/3 of the delegates agree, the entire procedure restarts and a new speaker will be chosen randomly again.

If delegates are malicious or not performing up to their job standards, citizens (token holders) can vote them out and bring in other delegates.

NEXT: 1. Read the Guide to Bitcoin Founder, Satoshi Nakamoto.