Smart Contract
A smart contract is a program stored on a blockchain that runs exactly as written when a transaction calls it.
What Is a Smart Contract?
A smart contract is code deployed to a blockchain such as Ethereum or Solana. Anyone can call it with a transaction, and the network executes it the same way for everyone. Tokens, decentralized exchanges, lending protocols and NFT collections are all smart contracts.
Interacting with a contract means signing a transaction whose effect depends on the contract's code: an approval, a swap, a transfer of every token the contract is allowed to move. A bug or a malicious contract can lose funds, and confirmed transactions cannot be reversed.
For hardware wallet users the key question is whether the device can decode the call (clear signing) or only shows raw data (blind signing).
A blockchain is a shared, append-only record of transactions kept by many independent computers, so no single party can rewrite it.
Read full definitionEthereum is a decentralized blockchain platform that enables smart contracts and decentralized applications (dApps). Its native cryptocurrency is Ether (ETH).
Read full definitionSolana is a high-performance layer-1 blockchain platform that enables fast, low-cost transactions using Proof of History and Proof of Stake. Its native token is SOL.
Read full definitionA token is a digital asset on a blockchain that represents value, ownership, utility, or access rights. Examples include ERC-20 tokens on Ethereum.
Read full definitionA decentralized exchange (DEX) is a set of smart contracts that swaps tokens directly from the user's own wallet, without an account or a custodian.
Read full definitionA lending protocol is a DeFi smart contract platform on blockchain where users lend crypto to earn interest and borrow assets using collateral.
Read full definitionAn NFT (Non-Fungible Token) is a unique digital asset stored on a blockchain, representing ownership of a specific item, such as artwork, music, or virtual goods.
Read full definitionIn cryptocurrency, a swap is the direct exchange of one token for another on a blockchain, often via decentralized exchanges (DEXs) without intermediaries.
Read full definitionClear Signing is a process in blockchain where transaction data is displayed in human-readable form before being signed, ensuring transparency and preventing blind signing risks.
Read full definitionBlind signing is the process of signing a transaction without viewing its contents, typically used in hardware wallets for enhanced security.
Read full definitionReal-World Examples
Example 1: A swap on a decentralized exchange calls its router contract, which takes one token and returns another in the same transaction.
Example 2: A fake airdrop site asks the user to sign a call to a malicious contract that moves their tokens.
In cryptocurrency, a swap is the direct exchange of one token for another on a blockchain, often via decentralized exchanges (DEXs) without intermediaries.
Read full definitionA decentralized exchange (DEX) is a set of smart contracts that swaps tokens directly from the user's own wallet, without an account or a custodian.
Read full definitionA token is a digital asset on a blockchain that represents value, ownership, utility, or access rights. Examples include ERC-20 tokens on Ethereum.
Read full definitionAn airdrop is a free distribution of cryptocurrency tokens to numerous wallet addresses, often to promote a project, reward users, or build community.
Read full definitionReady to Choose a Secure Wallet?
Use our tools to find the right hardware wallet for your needs.