Understanding Bitcoin's security assumptions and defensive strategies
Bitcoin's security is built on cryptographic principles and economic incentives. The network's resistance to attacks depends on the computational cost required to overcome the honest majority of miners.
The network remains secure as long as honest miners control more than 50% of the total hashrate, making attacks economically unfeasible.
Once transactions are buried under several blocks, the computational cost to reverse them becomes exponentially higher.
A distributed network of miners prevents any single entity from controlling the network or censoring transactions.
Understanding potential attack vectors helps in developing effective defensive strategies:
An attacker attempts to spend the same Bitcoin twice by creating a longer chain that excludes their original transaction. Defense requires sufficient confirmation depth and monitoring for chain reorganizations.
Miners withhold blocks to gain an unfair advantage. This strategy becomes profitable when controlling more than 25% of hashrate, highlighting the importance of maintaining decentralization.
Miners could potentially censor specific transactions or addresses. A diverse mining ecosystem with many independent operators reduces this risk.
Large Bitcoin holders can enhance network security through strategic mining deployment:
Key metrics for evaluating network security:
Total computational power securing the network. Higher hashrate means greater security but also higher attack costs.
Adjusts every 2016 blocks to maintain 10-minute block times. Rising difficulty indicates growing network security.
Measures decentralization by counting the minimum number of entities needed to control 51% of hashrate.
Effective defensive mining requires systematic threat assessment: