Blockchain//Wallet//Signing

- Metamask receives signing requests from DApps, shows them to the user, signs with the local private key.

Metamask receives signing requests from DApps, shows them to the user, signs with the local private key.

personal_sign: sign arbitrary data for off-chain authentication — no transaction created.

eth_sendTransaction: Metamask signs the transaction and sends it to the RPC node — standard DApp flow.

Admin Faucet pattern: backend signs with a server-side key (from .env) — solves the "chicken and egg" funding problem.

EIP-712: structured data signing includes the contract address in the domain hash — prevents cross-contract replay.