algo-blockchain-smart-contractlisted

# Smart Contracts ## Overview Smart contracts are self-executing programs stored on a blockchain that automatically enforce agreement terms when conditions are met. Primarily written in Solidity (Ethereum/EVM) or Rust (Solana). Once deployed, code is immutable — bugs cannot be patched without migration. Security is critical as exploits are irreversible. ## When to Use **Trigger conditions:** - Automating multi-party agreements that execute without intermediaries - Building token-based systems (NFTs, DeFi, governance) - Creating transparent, auditable business logic on-chain **When NOT to use:** - For simple CRUD operations (use a database) - When business logic changes frequently (immutability makes updates costly) - When off-chain data is the primary input (oracle dependency is risky) ## Algorithm ``` IRON LAW: Deployed Smart Contracts Are IMMUTABLE — Bugs Are Permanent Once deployed, contract code cannot be changed. A bug that loses funds is IRREVERSIBLE. There is no "hotfix" or "rollback" (unless the contract includes an upgrade proxy pattern). Security audit BEFORE deployment is not optional — it is the only protection. ``` ### Phase 1: Input Validation Define: contract purpose, participants, conditions, state variables, access controls. Determine: which logic MUST be on-chain vs which can be off-chain. **Gate:** Business logic specified, on-chain necessity justified. ### Phase 2: Core Algorithm **Design:** 1. Define state variables (stored on-chain, costs gas) 2