Extended Private Key (Xprv)

An extended private key (xprv) is a type of private key used in hierarchical deterministic (HD) wallets, allowing you to generate a tree of child private keys from a single source. Popularized by BIP 32, this approach means you can back up one xprv and later restore every wallet address and key it generates, making management and recovery much easier.

While the terms are sometimes mixed up, a master private key refers specifically to the root xprv created directly from a wallet’s seed, while any xprv at other points in the tree can also generate its own child keys.

Security is critical: leaking one private key exposes only its corresponding funds, but leaking an xprv endangers all funds derived from it and its descendants. You can recognize extended private keys by their 'xprv' prefix, followed by a long alphanumeric string.