Private key
A private key is a secret number that lets you sign transactions and spend the corresponding Bitcoin — whoever owns the key owns the bitcoin.
A private key is a 256-bit random number — practically infinite combinations (2^256). From this number, the public key is derived via elliptic-curve cryptography (secp256k1), and from that the Bitcoin address. Whoever has the private key can spend; losing it is definitive loss. 'Not your keys, not your coins' is Bitcoin self-custody's defining slogan.
Example
A typical private key in WIF format: L1aW4aubDFB7yfras2S1mN3bqg9nwy6bkyC3f7GMX9dAkJN6YxkZ. These 52 characters give full control over all funds on the corresponding address.
Frequently asked questions
What if I lose my private key?
Your bitcoins are unreachable to everyone, including you. No customer service can recover them. Estimates: 3-4 million BTC are permanently lost.
Related terms
Further reading
- → Our service: Bitcoin sector