Bip39 Pub Dev So long as your mnemonic phrase is stored Secure, no-one can take Charge of your assets even if the thief receives your cellphone and opens your App. Nearly all of folks compose the phrases on paper, but they are often saved in all kinds of other approaches: https://businessbookmark.com/story4151322/bip39-recovery-seed-word-list-the-definitive-guide-to-bip39-phrase