Intro
The consensus mechanism of any Blockchain technology ensures data is valid and consistently replicated over all nodes in the network. Bitcoin introduced the Nakamoto consensus. Bitcoin system is a well known implementation of blockchain technology in distributed transaction-based system. Although, certain loop holes have been recognized with the Nakamoto concensus.
Problems
1. Network nodes compete to store a set of one or more transaction in a new block of the blockchain. They solve a complex computational maths problem called a mining proof-of-work. Each block as a size of 1MB. This causes problems with speed of processing transactions. A block can only process 3–7 transactions per second.
2. Another identified problem is the lack of permanent record of transactions that are irreversible on the blockchain called Finality. With enough hash power malicious participants can alter transaction history and cause double spending attack if there is enough incentive and financial viability. This concensus uses extra measures called proof-of-work(POW) which further impedes its scalability because of the need of multiple comfirmation.
This identified problems geared the need to improve on Bitcoins trilemma: Speed, Security and Decentralization by other distributed ledger projects. They tried reducing the time needed in generating a block, introduced bigger blocks, implemented EOS’S delegated Proof-of-Stake (DPoS) but still yet to profer a lasting solution. Bitcoin Next Generation introduced a network node that acts as a leader node. This leader nodes process transaction and adds new blocks to the bitcoin blockchain which slightly reverts Bitcoin from a distributed system to having a single leader node. Failure of the leader node can cause failure of the system.
Another problem of distributed system is Byzantine fault problem. It requires nodes to agree on a strategy to reach a consensus to avoid system failure. Practical Byzantine Fault Tolerance (PBFT) introduced in new Orleans 1999 proposed a two round peer to peer message exchange technique to achieve consensus. It is called a mesh communication network due to communication of nodes to reach a consensus. A fault tolerance that permits a certain number of faulty nodes can be achieved in the PBFT. PBFT is not efficient when the system is scaled up. Communication cost increases as number of nodes increases in the PBFT system which again results in scalability problem.
Tendermint/Casper were prominent blockchain in 2018, they brought to public two new variants of PBFT and retrofitted it with linearity which implies that only linear communication cost would be levied on network participants..Although they let go-off responsiveness which refers to a dynamic where appointed leaders of PBFT can generate after receiving a certain number of communications rather than waiting for a fixed delay. HotStuff/LibraBFT introduced a protocol to modify the mesh communication network of PBFT system.In HotStuff communication complexity is low due to communication of each node.
However, Cypherium consensus algorithm called CypherBFT overcomes this disadvantages by providing a distributed transaction system. This sytem has a group of validator nodes or committee of validator nodes known to each other in a network but indistinguishable to other nodes in the network. The system reconfigures one or more validator nodes in the group based on result of POW challenges. A network node may become a new validator node in a committee based on proof -of –stake (POS) consensus which in turn replaces another existing validator node in the group,
Conclusion
This has given an overview of the driving force for Cypherium consensus architecture called CypherBFT due to inadequacies of other distributed ledger projects e.g Bitcoin-NG to solve the trilemma in Blockchain technology. Cypherium almagamate old methodologies to make new technologies.It is the first permissionless Hotstuff based blockchain
