Smart Contract

A smart contract is a program that lives on a blockchain and runs exactly as written whenever someone calls it. It replaces a trusted middleman with code: if the conditions are met, the contract executes; if they are not, it rejects the transaction. On Ethereum, smart contracts are usually written in a language called Solidity and compiled to bytecode the network can run.

For real-world assets, the smart contract is the token. It keeps the ledger of who owns what, moves balances when someone transfers, and can enforce rules in code - block a transfer to a wallet that has not passed a whitelist check, pause itself in an emergency, or pay out a distribution pro rata to holders. A tokenized Treasury fund, for example, uses a contract to mint shares, restrict them to approved investors, and update value from an oracle.

The key trait is that the code is automatic and public. Anyone can read it, and no one can quietly change how a deployed contract behaves - most are immutable once live, though some include controlled upgrade or admin paths.

That automation is also the risk. A smart contract does precisely what its code says, including its bugs. A flaw can lock funds or let an attacker drain them, and because the code is public, attackers read it too. This is why serious issuers commission a smart-contract audit before holding real money, and why the legal claim behind a token must hold up off-chain as well.

Source: Ethereum docs (ethereum.org), as of 2026.