The Consensus Algorithm Trilemma – Are There Universal Solutions?

Consensus algorithms are as varied as one can dare to imagine. From the popular, considerably basic, but rather resilient Proof-of-Work that Bitcoin pioneered to so many others that other companies utilize, such as Proof-of-Stake with all its variants and even Proof-of-Authority. So there is definitely a wide variety available. However, what is clear is that there is no one single consensus algorithm to rule them all. Each has their strengths, and by implication also weaknesses, so their usefulness and validity vary from project to project.  

It is not uncommon to have a project roll out their own consensus algorithm variant; often inspired from existing ones, to be able to cater to their exact needs. There are still many remaining problems to be grappled with, that no one single consensus algorithm has solved. For example, resistance to hackers and complete decentralization are paramount issues. As is solving the problem of “isolation of the leader.”

This was the exact case with REMChain, a blockchain by REMME that used to store a certificate’s hash, state, public key, and expiration date. This decentralizes the Public Key Infrastructure making the system much more secure. Whilst exploring different consensus algorithms for the Blockchain, they developed their own system of achieving what they describe as

“a reliable and balanced algorithm that would guarantee the highest level of security as well as ensuring that every Masternode holder within the REMME ecosystem is fairly represented and incentivized to participate”.

A Masternode is a node capable of handling tasks such as certificate issuance or revocation which any user can, in theory, set up; provided they satisfy a number of criteria that all the other connected Masternodes process.

And this is where REMChain’s Proof-of-Service consensus mechanism comes in. It makes a pseudorandom selection of Masternodes, which together with other factors such as a reputation, in form of stake and a bet, gives the right to sign the block containing the key information. This provides for consistency and fault tolerance.

Each of the components of the algorithm was created to solve a certain problem:

Every time a block is produced, the process starts with forming a committee. Assigning this role to committees – the number of masternodes that are able to offer blocks – helps the algorithm to ensure that the blockchain maintains work of high quality.

Committees are formed from nodes that have a high reputation which serves as an indicator of trust. Reputation – based on the initial stake and node’s performance results – provides blockchain reliability and protection against attacks, as well as ensuring the fair distribution of rewards.

The masternode owner can raise their chances of being selected to close the block with help of a bet. At the same time, the bet serves as a kind of pledge. It is taken when the node is selected to sign the block but did not coincide with the remaining blocks offered by the committee members. The bet helps protect the blockchain from non-active or non-responsible nodes.

When asked about REMChain, the CEO of REMME, Alex Momot, said that,

“REMME has created a fair, transparent and decentralized system that is free of favoritism. To ensure that no single “whale” with a large number of tokens could harm our ecosystem, we implemented reputational and betting-related stipulations. In doing so, we minimized the potential for attacks when a single token-holder may hold in quantity of masternodes”.

Alex is no newcomer to blockchain, as he has more than ten years of experience in IT and he has been working in the blockchain space since 2013. In 2014 he ran BitX, a start-up that allowed people to pay for telecom and other everyday services in bitcoin. He describes himself as being “passionate about blockchain-driven business model innovation, cybersecurity, and technology development.”

As we closed off 2018 it has become all the more apparent that while the value of cryptocurrencies continues facing challenges compared to the previous year, the number of projects making practical uses of the Blockchain is constantly on the rise, which bodes well for the technology and its adoption heading into 2019.