Bip39 Vs Slip39. The passphrase isn't selected from the predefined list of 2048 words – it might be any word or phrase you decide on. Anybody else who discovers the phrase can steal the bitcoins. It should be stored top secret, one example is it need to not be typed https://push2bookmark.com/story18814912/bip-39-https-linktr-ee-bip39-top-guidelines-of-bip39-mnemonic