Get the extension What is message signing in crypto?
Message signing is using your private key to sign text rather than a transaction. It moves nothing on the chain. Sites use it to prove you own an address, for example to log in with Sign-In with Ethereum (EIP-4361).
Why it matters
A plain login message is harmless. But signatures can also authorise things off-chain: a gasless token permit or an exchange order is a signed message too, and it can be used later to move your funds.
How Locker Protocol Wallet handles it
Locker Protocol Wallet checks Sign-In with Ethereum requests: a login message that names another site than the one asking is refused, since that is how a fake site opens a session on the real one. Every message, like every transaction, is signed on Locker Vault after you read it there.
Questions
Can signing a message drain my wallet?
A plain text message cannot. A typed-data signature such as a permit can authorise a transfer later, which is why a wallet must show you exactly what the message contains.
Does message signing cost gas?
No. The signature is made on your device and sent to the site, not to the blockchain.