hash – Is PoW an essential component of blockchain?
The short answer is yes. PoW is an essential component of blockchain.
First, Bitcoin proof-of-work chain It can be considered a consensus mechanism.
An article proposing a Bitcoin network ends with the following idea: “Proof-of-Work Chain” It consists of two parts: a proof-of-work mechanism and a chain process, and this combination can be viewed as a consensus mechanism.
However, Bitcoin’s “Proof-of-Work Chain” The mechanism does not fully satisfy ‘.agreement‘This is a necessary condition for the consensus mechanism.
In Bitcoin “Proof-of-Work Chain”, especially during the creation of new blocks, temporary forks may occur. Miners can simultaneously find valid solutions to cryptographic puzzles, resulting in valid blocks competing. This results in different parts of the network initially supporting different blocks.
Although the network eventually converges to a single chain and the longest chain rule determines the standard blockchain, there are brief periods when consensus is not unanimous and different nodes may temporarily support different blocks. This temporary fork phenomenon is inherent to the probabilistic nature of Bitcoin’s proof-of-work mechanism.
The debate over whether Bitcoin’s combination of proof-of-work and chain processes constitutes a consensus mechanism has not yet been resolved. The Bitcoin network mechanism does not meet all the conditions of a consensus mechanism, including termination, unified integrity, contracting, and unified validity. (Summons)
(Summons) Kshemkalyani, Ajay D., and Mukesh Singhal. Distributed Computing: Principles, Algorithms, and Systems. Cambridge University Press, 2011.
It is important to note that the Bitcoin network designers proposed a ‘proof-of-work chain’ as a consensus mechanism, which implies a combination of proof-of-work and chain processes rather than proof-of-work alone.
Therefore, the initial term ‘proof-of-work chain’ may be more accurate than ‘blockchain’ in that it emphasizes the integration of proof-of-work and chaining processes. Separating these two elements will impact the entire network, including the efficiency of the chain process without proof-of-work.
Without PoW, linked blocks can be completely replaced by altered chains. This is true whether in a permissioned network or the lack of Sybil or DoS attack prevention mechanisms such as sufficiently difficult proof-of-work proportional to the total hashing power of the network.
In the absence of PoW, it is possible to replace the entire blockchain with a new valid chain, and since every block is created based on the hash of the previous block, you can create an existing blockchain and replace it with a new valid chain.
Therefore, yes. PoW is an essential component of blockchain.
A blockchain system without PoW is meaningless in preventing changes to transaction history.
This is despite Bitcoin’s proof-of-work chain having its own issues and inefficiencies, such as consuming large amounts of energy while processing only 7 to 10 transactions per second.
Important Note 1:
It is incorrect to claim that a blockchain without PoW is meaningful because Ethereum no longer uses PoW. The blockchain structure does not contribute to the security of Ethereum after PoW is removed. In current versions of Ethereum, security is provided by different parameters and factors. In time this will become clear.
Important Note 2:
I know that many blockchain platforms simply connect stored data. That’s why I started this discussion. Without a sufficiently difficult PoW, if someone can tamper with one block, they can tamper with the rest. Conversely, if even a single block cannot be manipulated, it is not because of a ‘chained block’. However, PoW_Chain does not. The reason why blocks cannot be manipulated in PoW_Chain is because PoW of sufficient difficulty exists. In PoW_Chain, someone can manipulate one block, but not two blocks, and this is because of “On-Chain PoW”.
Additional information and explanation:
- PowerPoint with commentary (click link)
- Doctoral thesis (click link)
- Video presentation (click link)
- Permissioned vs. Permissionless Blockchain: How and Why There is Only One Right Choice (click link)