Overview
Blockchain security involves the use of cryptographic techniques and consensus mechanisms to ensure the integrity and availability of a distributed ledger. While the underlying technology is often secure, the applications and platforms built on top of it are frequent targets for attackers.
Key Security Features
- Immutability: Once data is written to a block, it cannot be changed without changing all subsequent blocks.
- Decentralization: No single point of failure; the ledger is maintained by many nodes.
- Consensus Mechanisms: Rules (like Proof of Work or Proof of Stake) that ensure all nodes agree on the state of the ledger.
Common Threats
- 51% Attacks: An attacker gains control of more than half of the network's mining power.
- Smart Contract Vulnerabilities: Flaws in the code that governs transactions.
- Exchange Hacks: Attacks on the platforms where cryptocurrencies are traded.