A 24 word mnemonic FIDO backup seed can fit AES256 encrypted in a 1K NFC tag, which come in sizes as small as a grain of rice. You can store it in a subdermal

A 24 word mnemonic FIDO backup seed can fit AES256 encrypted in a 1K NFC tag, which come in sizes as small as a grain of rice. You can store it in a subdermal implant, under the sole of your shoe, a belt buckle, or in a finger ring or other jewelry. Options are endless.