Consensus mechanisms in cryptocurrencies explained

Blockchain technology, the foundation that cryptocurrencies run on, makes it possible to maintain a public record (ledger) of transactions that is immutable and tamper-proof.

Recording and confirming transactions on a blockchain requires a consensus mechanism. This mechanism determines how the participants in a cryptocurrency network agree on which transactions are valid and will be added to the blockchain. However, different cryptocurrencies use different consensus mechanisms, some of which are better suited to specific needs and use cases.

Let’s look at some of the most common consensus mechanisms in use today.

What is Proof of Work (PoW)

Proof of Work (PoW) is a mechanism used by cryptocurrencies to confirm and validate the transactions made on the network. Instead of a central authority that checks and confirms transactions, PoW uses the computing power of many users to solve problems.

These problems are very hard to solve, but once the right solution has been found, it is easy to verify. Participants known as “miners” compete to find the right solution to these problems, and the first one to do so announces it to the network.

Once the correct solution has been found and verified, the block of transactions is added to the blockchain, the public distributed ledger that records all transactions. The miner who found the solution is rewarded with newly created cryptocurrency and the users’ transaction fees.

PoW secures the network because it takes a lot of computing power to solve the problems. It also makes attacks by malicious users difficult, since they would need enormous computing costs to validate transactions.

What is Proof of Stake (PoS)

Proof of Stake (PoS) is a consensus mechanism used by cryptocurrencies to confirm transactions and add new blocks to the blockchain. Instead of using computing power, as in Proof of Work (PoW), Proof of Stake (PoS) is based on the concept of staking.

In Proof of Stake (PoS), users hold and lock up cryptocurrency in a special wallet. These coins act as collateral, or a “stake,” for the security and operation of the network. The more coins a user has staked, the higher their chances of being selected to confirm transactions.

As users stake their coins, they are randomly selected by the cryptocurrency’s protocol to carry out the duties of confirming transactions and producing new blocks. When they perform these duties successfully, they are rewarded with new coins or a share of the transaction fees on the chain.

Proof of Stake (PoS) has some advantages over PoW. It uses less energy, since it doesn’t require massive computing power to solve complex problems. It also encourages users to hold their coins, creating a more stable community and reducing the chances of centralized control.

However, even though Proof of Stake (PoS) is an effective mechanism, measures must be taken against possible attacks by malicious participants. These attacks include Sybil attacks and the Nothing at Stake problem, which have to be addressed carefully with effective network protection mechanisms.

What is Delegated Proof of Stake (DPoS)

Delegated Proof of Stake (DPoS) is a consensus mechanism used by cryptocurrencies to solve coordination problems and determine which nodes will confirm transactions and produce new blocks.

In Delegated Proof of Stake (DPoS), coin holders can vote for the “delegates” or “witnesses” who will take on the role of confirming transactions and creating new blocks. These delegated nodes are responsible for the security and operation of the network.

Coin holders can vote for delegates based on their trust and preferences. The nodes that receive the most votes take the delegate slots and perform their role on the network.

In this way, Delegated Proof of Stake (DPoS) makes transaction confirmation faster and more efficient, since it is handled by a small number of delegates chosen by the user community. DPoS also offers mechanisms for dealing with malicious participants in order to keep the network secure.

What is Proof of Authority (PoA)

Proof of Authority (PoA) is a consensus mechanism used by cryptocurrencies to confirm transactions and produce new blocks on the blockchain. Put simply, in Proof of Authority (PoA), the transaction validators are predefined, authorized nodes of the network.

These validators have already proven their identity and trustworthiness, which allows them to confirm transactions without having to solve complex computational problems, as happens in Proof of Work (PoW).

Nodes are usually authorized by the cryptocurrency’s community itself or through other identity verification mechanisms. This ensures that only trusted and experienced entities can take part as validators.

Using Proof of Authority (PoA) allows for high speed and scalable network performance, since validators are predefined and authorized, with no need for a competitive race to find new blocks as in PoW.

However, one of the drawbacks of Proof of Authority (PoA) is that validation is centralized, since validators are predefined and appointed by the cryptocurrency’s creators. This way of managing validators requires trust in the group that selects them and may raise concerns about the network’s security and independence.

What is Proof of Burn (PoB)

Proof of Burn (PoB) is a consensus mechanism used by some cryptocurrencies. Essentially, instead of having to show a lot of computing power (as in Proof of Work) or hold coins (as in Proof of Stake), in Proof of Burn (PoB) users “burn,” or destroy, part of their coins.

Specifically, the user sends an amount of cryptocurrency to a separate, unspendable address. This destroyed amount of cryptocurrency is called a burn. Users who choose to burn their coins show their commitment to the network and its shared purpose, making Proof of Burn (PoB) a kind of “proof of commitment.”

As with other consensus mechanisms, users who perform Proof of Burn (PoB) may be rewarded with new coins or earn the right to add new blocks to the blockchain, depending on the rules of the specific cryptocurrency.

Proof of Burn (PoB) is used by some cryptocurrencies to achieve security and consensus, requiring each user to make a “sacrifice” in order to participate in the network and confirm transactions.

What is Proof of Capacity (PoC)

Proof of Capacity (PoC) is a consensus mechanism used by some cryptocurrencies that is based on your computer’s storage space (hard drive or memory).

When you take part in the network and want to confirm transactions or produce new blocks, you have to show that you have dedicated a significant amount of storage space on your computer. This can be done by creating special files, known as plots, that take up a lot of space. The more space you dedicate, the higher your chances of being selected to create a new block or confirm transactions.

Unlike other consensus mechanisms such as Proof of Work, which requires a lot of computing power and energy, Proof of Capacity (PoC) is more environmentally friendly and affordable, since you just need storage space to participate. However, Proof of Capacity (PoC) takes longer at the start to set up the plots and fill the required space on your computer’s hard drive or memory, but once that’s done, you can take part in the network without any problem.

Proof of Capacity (PoC) is an alternative used by some cryptocurrencies to reach consensus and secure the network.

What is Byzantine Fault Tolerance (BFT)

Byzantine Fault Tolerance (BFT) is a mechanism used by cryptocurrencies to deal with the problem of malicious participants (Byzantine faults) on the network. Think of it as a test of the network’s resilience to malicious behavior.

In a cryptocurrency, there are nodes that participate in the network and are responsible for overseeing transactions and creating new blocks. Some of these nodes may be malicious, meaning they may try to deceive the network, disrupt its operation or carry out unwanted transactions.

Byzantine Fault Tolerance (BFT) tackles this problem by making nodes cooperate and reach consensus when deciding on transactions and block creation. As long as malicious nodes make up less than about a third of the network, it keeps operating correctly and stays secure.

Byzantine Fault Tolerance (BFT) is important for a cryptocurrency’s security and reliability, because it ensures that malicious actions cannot disrupt the network’s operation and cause problems such as double-spending or compromise the security of the coins.

What is Proof of Activity (PoA)

Proof of Activity (PoA) is a consensus mechanism that combines two different mechanisms to ensure the security and operation of the network.

The first mechanism is Proof of Work (PoW), like the one used by Bitcoin. In PoW, miners compete to solve difficult computational problems. The first to find the correct solution earns the right to add the next block to the blockchain and receive a reward.

The second mechanism is Proof of Stake (PoS). In PoS, participants hold and lock up coins in a special wallet. The amount of coins someone holds affects their chances of being selected to produce a new block or confirm a transaction.

In Proof of Activity (PoA), users follow this two-step process. First, they use PoW to solve the difficult computational problems and create new blocks. Then they use PoS, depositing the newly created coins in their wallet to prove their commitment to the network.

In this way, Proof of Activity (PoA) combines the advantages and security of both mechanisms, offering a highly effective and secure way to reach consensus and run the cryptocurrency.

What is Proof of Stake Velocity (PoSV)

Proof of Stake Velocity (PoSV) is a consensus mechanism that is a variant of Proof of Stake (PoS). The purpose of Proof of Stake Velocity (PoSV) is to encourage user participation and the circulation of coins on the network.

Put simply, in Proof of Stake Velocity (PoSV), users are rewarded based on two key factors:

Coins held (Proof of Stake):
Users must hold coins in their wallet, which act as collateral for the security and operation of the network. The more coins a user holds, the higher their chances of being selected to confirm transactions and produce new blocks.

Coin circulation (Velocity):
In addition, Proof of Stake Velocity (PoSV) takes into account how actively each user’s coins move. This means that if a user moves their coins frequently (e.g. frequent transactions), they are more likely to receive larger rewards.

Overall, Proof of Stake Velocity (PoSV) encourages users to hold their coins rather than sell them or move them often. This mechanism is designed to promote economic stability and network security, making the cryptocurrency more resilient and sustainable in the future.

What is Nakamoto Consensus

Nakamoto Consensus is the consensus mechanism used by Bitcoin and many other cryptocurrencies. Put simply, it can be described as the way the Bitcoin network and other crypto networks reach agreement on the transactions that take place.

Here’s how it works: in a cryptocurrency that uses Nakamoto Consensus, the transactions made by users are grouped into blocks and must be confirmed. To do this, participants in the network known as miners compete to solve a complex computational problem. The first to find the correct solution earns the right to add the block to the blockchain.

The blockchain is a chain of blocks, where each newly added block contains the new transactions. Each block also contains a reference (hash) to the previous block, linking them together.

A miner needs a lot of computing power to solve the problem, and that is exactly the point: solving it takes time and resources. However, once a miner finds the correct solution, they can add the new block to the blockchain and receive a reward for their effort, usually in the form of cryptocurrency.

In this way, Nakamoto Consensus allows transactions to be confirmed without a central authority in a relatively simple way, while also keeping the network secure. It is a key reason for the success and widespread adoption of Bitcoin and other cryptocurrencies that use this mechanism.

Conclusion

Consensus mechanisms are the backbone of cryptocurrencies, ensuring the security, integrity and trustworthiness of their transactions. Each mechanism has its advantages and limitations, and the choice depends on the requirements and goals of the specific cryptocurrency. With ongoing development and innovation, consensus mechanisms will keep evolving and adapting to the future needs of the crypto market.