Seed Phrase

A seed phrase, also called a recovery phrase or mnemonic, is a human-readable backup of all the private keys in a wallet. It is generated when the wallet is created, using a standard called BIP-39 that maps random data to words from a fixed list of 2,048 English words. From those words the wallet can derive every key and address it will ever use.

Because the phrase recreates the whole wallet, it is the most sensitive thing a crypto user owns. If a phone is lost or a hardware wallet breaks, entering the seed phrase into a new wallet restores full access. If a thief obtains the phrase, they have the same access and no transaction can be reversed.

Best practice is to write the phrase on paper or stamp it into metal, store it somewhere physically secure, and never photograph it, type it into a computer, or store it in cloud notes. Legitimate wallets and companies will never ask for it. Most thefts of self-custodied crypto involve a seed phrase that was entered into a fake website or shared with a scammer posing as support.