Execution Blockchain Primitive
Smart Contracts
Self-executing programs that run on blockchain networks
What are Smart Contracts?
Smart contracts are self-executing programs stored on a blockchain that automatically execute when predetermined conditions are met. They enable trustless agreements without intermediaries.
Key Characteristics
Immutable
Once deployed, smart contract code cannot be changed (unless designed with upgradability)
Deterministic
Same inputs always produce same outputs across all nodes
Transparent
Code is publicly visible and auditable
Autonomous
Execute automatically without human intervention
How They Work
- Developer writes contract code
- Code is compiled to bytecode
- Contract is deployed to blockchain
- Users interact via transactions
- State changes are recorded on-chain
Use Cases
DeFi (Decentralized Finance)
- Lending and borrowing protocols
- Decentralized exchanges
- Yield aggregators
NFTs
- Digital art and collectibles
- Gaming assets
- Real-world asset tokenization
DAOs
- Governance voting
- Treasury management
- Proposal execution
Other Applications
- Supply chain tracking
- Insurance automation
- Identity verification
Programming Languages
| Language | Platform | Notes |
|---|---|---|
| Solidity | EVM chains | Most popular |
| Vyper | EVM chains | Python-like, security-focused |
| Rust | Solana | High performance |
| Move | Aptos, Sui | Resource-oriented |
Security Considerations
Common vulnerabilities include:
- Reentrancy attacks
- Integer overflow/underflow
- Access control issues
- Oracle manipulation
Best practices:
- Thorough testing
- Professional audits
- Bug bounty programs
- Gradual deployment