Difference between consensus mechanism POW and POS - DotWallet

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Difference between consensus mechanism POW and POS
2019.12.05

 

The consensus mechanism is very important in the blockchain system. It is one of the key technologies to ensure the security of data on the blockchain. It is the basis for building trust in the blockchain.

 

Now the mainstream consensus mechanisms in blockchain projects are Proof-of-Work (POW) and Proof-of-Stake (POS). What is the difference between the two?

 

The Proof-of-Work Mechanism (POW) determines the accounting right by the computing power, and determines the probability of obtaining the accounting right according to the percentage of the computing power held in the total computing power. It is not difficult to understand that POW is often used in our reality, such as the win rate and K / D ratio in video games. A certain win rate in a large number of battles can explain the strength of players.

 

In the blockchain system, the POW system uses the qualified HASH as the work result. Nodes need to continuously consume computing power to perform HASH calculations to find the desired random number. The verification node is called "miner" and the random number lookup process is called "mining". "Mining" has three important functions: issuing new currency, maintaining the payment function of the system, and ensuring system security through computing power.

 

The advantages of the consensus mechanism POW are obvious to all: the algorithm is simple, the nodes can be freely entered, and the degree of decentralization is high; cracking the system requires mastering at least 51% of the computing power, which requires a great cost and high security; block producer The selection is implemented by the node solving hash function, and the whole process does not require human involvement.

 

The proof of stake (POS) consensus mechanism is based on the number of coins held and the time it is held to determine the right to book. The number of coins held and the percentage of time held in the total system determine the probability of obtaining this accounting right. We can use the stock to understand the POS method. The stock is used to record the proof of equity, and it also represents voting rights and income rights. After the stock is created, in addition to the additional issue, the number of shares cannot be increased, and the stock can only be transferred to obtain.

 

The advantage of POS is that it does not need to consume energy and hardware equipment, and shortens the block generation time and confirmation time, and improves the system efficiency. The security of a POS depends on the holder and has nothing to do with it.