Do you want to learn more about Ethereum and how it works? Do you want to uncover a treasure trove of knowledge about its Consensus mechanism? Don't worry if you're not familiar with it, join me for a short ride, and by the end, you'll have a treasure map to find everything you need!
Ethereum's consensus layer is a Proof of Stake (PoS) system that relies on validators who lock up their ETH to gain block-producing power. With more than 400,000 validators on the beacon chain, this decentralized network ensures security and efficiency. Validators deposit 32 ETH into the beacon chain deposit contract and participate actively in proposing and attesting to blocks. Each slot occurs every 12 seconds, with one validator proposing a block and others, known as the committee, attesting to it. An epoch consists of 32 slots (~6.4 minutes), where blocks undergo phases of being proposed, justified, and finalized, requiring a supermajority (2/3) of validators for finalization.
Gasper, the combination of Casper FFG and the LMD-GHOST fork choice algorithm, governs Ethereum's consensus layer.
- Casper FFG upgrades blocks to "finalized," ensuring new entrants sync with the canonical chain.
- LMD-GHOST uses accumulated votes to handle forks.
Validators must avoid double voting and surrounding votes, which could lead to penalties. The consensus client layer enforces these rules, ensuring validators act honestly.
Security mechanisms within Ethereum's PoS system include slashing and the inactivity leak.
- Validators proposing multiple blocks for the same slot or attesting to multiple blocks within the same epoch face slashing penalties, which can burn up to 1 ETH before the validator is removed from the network.
- The inactivity leak activates if the consensus layer fails to finalize for more than four epochs, gradually reducing the stake of inactive validators until the active ones regain a supermajority.
- This "self-healing" mechanism ensures both safety and liveness of the network, making attacks more challenging and costly.
Despite these security measures, potential attacks exist. A malicious actor controlling 33% of the stake can delay finality, while controlling 34% can create a permanent chain split. With 51% control, an attacker can censor transactions and dominate block proposals. Controlling 66% allows manipulation of both the blockchain’s history and future. However, the high cost and complexity of such attacks, combined with Ethereum's robust slashing penalties, make these scenarios highly unlikely. The network's design ensures that even large-scale attacks face significant economic and operational hurdles.
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