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BIP39 seed phrase is a group of words of different length compiled from private or extended private BIP44 HD key for more convenient storage. The seed phrase itself is not encrypted and is a straight and sole source of your keys. Each user is faced with the necessity to store a copy of their seed phrase securely, so that it can serve as a backup in case of the following: Wallet password is lost or device where wallet is installed is lost. There are two approaches to storing data in digital and physical storage: digital and offline.