What Is Private Key?
Also known as: Private Key, Secret Key
In short
A private key is a secret number that gives the authority to spend the assets at a cryptocurrency address and to sign transactions. Whoever holds the private key effectively controls the funds at that address.
On networks such as Bitcoin and Ethereum, a private key is a 256-bit value chosen at random from an extremely large range of numbers. Using elliptic curve cryptography, the public key is derived from this key, and the wallet address is derived from the public key. This derivation is one-way: when the address or public key is known, computing the private key is practically impossible. When a transaction is sent, the wallet signs it with the private key, and the network verifies the signature with the public key.
Modern wallets usually derive private keys from a 12- or 24-word recovery phrase (seed phrase); this phrase serves as a backup of all the keys in the wallet. The community saying 'not your keys, not your coins' is a reminder that for assets held on a custodial exchange, the private key is held by the service provider, not the user.
If the private key is lost, access to the funds can be lost permanently; if it is stolen, the attacker can transfer the assets irreversibly. For this reason, the private key and recovery phrase should not be shared with anyone, should not be stored as a screenshot or cloud note, and, if possible, should be kept in offline environments such as a hardware wallet. People who introduce themselves as support staff and ask for this information are almost always scammers.
Last updated: · This content is for information purposes only and is not investment advice.