What is a 51% Attack?
The short answer
A theoretical attack where one entity gains control of the majority of a network's computing or staking power, allowing it to manipulate transactions.
Extremely difficult and expensive to pull off on large, established networks like Bitcoin, which is part of why a high hash rate is considered a genuine security feature.
Related terms
Full glossaryNode
A computer that keeps a copy of a blockchain's full transaction history and helps verify new transactions.
Non-Custodial Wallet
A wallet where only you hold the keys — full control, and full responsibility.
Proof of Stake
A consensus method (used by Ethereum) where network security comes from participants locking up coins as collateral.
Volatility
How much and how quickly a price moves, in either direction.
DCA (Dollar-Cost Averaging)
Buying a fixed amount on a regular schedule, regardless of price, instead of trying to time the market.
Decentralization
Spreading control across many independent participants instead of one company, so no single party can change the rules…
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