Blockchain Security
Blockchain's security model is fundamentally different from traditional IT security. Instead of firewalls and access control, security relies on cryptographic guarantees, economic incentives, and network consensus.
Security Layers
┌──────────────────────────────────────────────┐
│ BLOCKCHAIN SECURITY LAYERS │
├──────────────────────────────────────────────┤
│ │
│ Layer 1: Cryptographic Security │
│ ├─ SHA-256 / Keccak-256 hashing │
│ ├─ Elliptic curve digital signatures │
│ └─ Merkle tree integrity │
│ │
│ Layer 2: Consensus Security │
│ ├─ PoW: 51% attack cost is massive │
│ ├─ PoS: Slashing for misbehavior │
│ └─ Network consensus prevents fraud │
│ │
│ Layer 3: Economic Security │
│ ├─ Attack costs exceed potential gains │
│ ├─ Stakers have skin in the game │
│ └─ Mining costs align incentives │
│ │
│ Layer 4: Smart Contract Security │
│ ├─ Code is law (and bugs are permanent) │
│ ├─ Audits and formal verification │
│ └─ Bug bounties and security practices │
└──────────────────────────────────────────────┘
Common Attack Vectors
Security Best Practices
Never store private keys digitally — use hardware wallets.
Verify contract addresses before interacting — scammers deploy lookalike contracts.
Use multi-sig wallets for large funds — require multiple signatures for transactions.
Audit smart contracts before deployment — use established firms like Trail of Bits, OpenZeppelin.
Follow Checks-Effects-Interactions — prevent reentrancy by updating state before external calls.
Keep dependencies updated — known vulnerabilities in older library versions.