Ethsign

Ethsign refers to the process and tools used to produce an Ethereum digital signature, typically applied to a message or a transaction to prove ownership of an address and authorize actions on the network. In practice, ethsign is performed by a wallet or client with access to an account’s private key; the resulting signature allows anyone to verify that the holder of the private key approved the message without exposing it.

Mechanism: Ethereum uses the ECDSA over secp256k1. A message or transaction is hashed with Keccak-256. For personal messages, wallets often prepend a prefix such as “Ethereum Signed Message:\n” before hashing, to create a domain-bound signature. The final signature consists of the r, s, and v values; v enables public-key recovery to confirm the signer address.

Standards and methods: The Ethereum JSON-RPC interface includes eth_sign and personal_sign, which request a signature from the given address. EIP-191 formalizes the signing of personal messages, while EIP-712 specifies signing of typed structured data for better security and user experience.

Applications: Ethsign is used by wallets to authorize transactions, by decentralized applications for authentication and contract interactions, and by services that rely on signature verification to prove ownership of an address.

Security: Users should be cautious when signing unknown data, as signatures can authorize unintended actions. Signing messages without proper domain binding can allow replay or misrepresentation across networks; using prefixed or structured data (as per EIP-191 and EIP-712) helps mitigate risks. Employ established libraries and wallet implementations to avoid common pitfalls.

See also: Ethereum, ECDSA, Keccak-256, eth_sign, personal_sign, EIP-191, EIP-712.