Crypto glossary
EIP-712 typed data signing
EIP-712 is the Ethereum standard for signing structured, typed data, so wallets can show readable fields instead of an opaque hex string before the user signs.
Before EIP-712, apps that needed an off-chain signature often asked users to sign a raw hash or an unreadable blob. EIP-712 defines how to describe a message as named, typed fields, such as owner, spender, value and deadline, and how to hash it together with a domain separator. The domain includes the app's name, version, chain ID and contract address, so a signature made for one app or network cannot be replayed on another.
It is now the format behind most off-chain approvals and orders on Ethereum: token permits, NFT marketplace listings, gasless order books, multisig transactions and many governance votes. Wallets display each field, and hardware wallets have gradually added clear signing for common EIP-712 messages so users can confirm what they approve on the device screen.
Readable is not the same as understandable. A user may see a list of addresses and numbers and still not realise they are listing an NFT for nothing or granting unlimited token access. Phishing kits rely on that gap. Signing an EIP-712 message costs no gas and leaves no trace until someone submits it.
Example
When listing an NFT, the marketplace asks the user to sign an EIP-712 order showing the item, price and expiry; the wallet displays those fields instead of hex.