Hash Consensus Problem Eth2
The Ethereum 2.0 network is introducing new consensus mechanisms to improve security, scalability, and decentralization. One of these changes is related to the hash functions used in the Proof-of-Work (PoW) mechanism. In this article, we will delve deeper into the concept of identical hashes in blocks and its implications for the validity of transactions.
Problem: Two Blocks with Identical Hashes
When a node solves two blocks in the Ethereum PoS consensus mechanism, it receives a reward in newly minted Bitcoins (or Ether, ETHER), as well as any transaction fees associated with those blocks. The hash function, which is used to validate blocks and ensure the integrity of the network, ensures that each block is linked to its previous state.
But what happens when a node tries to solve two blocks at the same time? In an idealized scenario, all nodes in the network would agree on the same valid chain. However, in reality, some nodes may try to exploit this situation by solving two blocks with identical hashes.
Problem: Transaction Validity
If two blocks have identical hashes, it means that the node attempting to solve these blocks successfully merged them without any errors or discrepancies. In this case, the resulting block would be considered valid and would include the previously mined Bitcoins (or Ether) along with any transaction fees.
However, this raises an interesting question: would solving two blocks with identical hashes be considered a valid transaction? The short answer is no, it wouldn’t.
Why not?
In the current Ethereum architecture, each block contains a unique set of transactions and their corresponding hashes. When a node solves two blocks at once, the resulting block will overwrite all existing data on the blockchain. This means that the previous state of the chain would be lost, making all transaction history prior to the two blocks being solved invalid.
Furthermore, if a node tries to solve two identical blocks, it will create a new chain with its own set of transactions and hashes. However, since each block has a unique hash, this new chain cannot be linked back to the previous one. This creates an infinite loop where nodes have to start from scratch every 2-3 blocks.
Solution: Two-Block Proof of Stake
Ethereum 2.0 was designed to solve the consensus hashing problem by introducing Proof of Stake (PoS) instead of Proof of Work (PoW). PoS validators are selected not based on their mining power, but on the amount of ether they hold in their wallet.
To solve the problem of two blocks having identical hashes, Ethereum 2.0 introduces a new mechanism called “two-block proofs”. A two-block proof is a block that contains a transaction and its corresponding hash, as well as a process for validating the stake. This ensures that each block has a unique set of transactions and their hashes.
Conclusion
In summary, in the current architecture of the Ethereum network, a solution of two blocks with identical hashes would not be considered valid. The resulting block would overwrite all existing data on the blockchain, making all previous transaction history invalid. To address this issue, Ethereum 2.0 introduces staking validation mechanisms that ensure that each block has a unique set of transactions and their hashes.
As Ethereum continues to evolve and improve its consensus mechanism, it is crucial to understand these fundamental concepts and their impact on the overall security and decentralization of the network.