Using Shamir Secret Sharing in Ardor
The Ardor and Nxt blockchain products use what BCNext, the developer of the first Nxt release, used to call a “Brain Wallet.” What he meant was that a single hard to crack passphrase (with 128 bits of entropy or more) is used to protect your account. The account private and public keys and the account address are all derived from this single passphrase.
Anyone holding the account passphrase can submit transactions from the account. If the passphrase is lost, the funds in the account are lost forever. If the passphrase is compromised, the attacker can steal all the funds.