Private key
Also known as: secret key
The secret cryptographic key that authorises spending from a crypto address; anyone with it controls the funds.
Definition
A private key is the secret number that signs transactions, proving ownership and authorising movement of crypto from an address. It must be kept secret — whoever holds it controls the assets. Public addresses are derived from it. For record-keeping, you never share private keys with tax tools; instead you connect via read-only API keys or public addresses, which is enough to reconstruct transaction history.
Example
You import your wallet into a tax tool using a public address only, never the private key, so the tool can read but not move funds.