Digital Signature
A cryptographic proof that a specific keyholder authorized a message, and that it hasn't been altered since.
When you send crypto, your wallet signs the transaction with your private key. The signature is unique to both the key and that exact transaction — change a single detail and it no longer checks out. Anyone can verify it using your public key.
This is what replaces a bank's authorization. The network doesn't need to know who you are; it only needs to confirm the signature is valid. That check proves you control the funds and that no one tampered with the amount or destination en route.
Related terms
The secret number that proves ownership of crypto and authorizes spending it; whoever holds it controls the funds.
Public KeyA key derived from your private key that others use to verify your signatures and that forms your address.
Public-Key CryptographyA system using a paired public and private key so anyone can verify a signature only the owner could make.
TransactionA signed instruction that moves value or data on a blockchain, recorded permanently once miners or validators confirm it.