Master key
Plain definition. On the XRP Ledger, the master key pair is the private key and public key that an account’s address is derived from; it can be disabled but never changed.
Technical definition. The XRP Ledger documentation defines the master key pair as a private key and a public key from which an account’s address is derived, so the two are intrinsically related; it cannot be changed or removed, only disabled. Only the master key pair can authorize certain actions: sending an account’s very first transaction, disabling the master key pair, permanently giving up the ability to freeze, and sending a special key reset transaction with a transaction cost of 0 XRP. For secp256k1 keys, the master public key is derived by adding the intermediate public key to the root public key.
On this site
On this site, Master key comes up in Is XRP’s cryptography at risk from quantum computers?, What XRP Ledger features can protect my account (regular keys, multi-signing, disabling the master key)? and Can I lose my XRP without anyone hacking me?.
Source
Cryptographic Keys (xrpl.org), read October 1, 2026.