Leakable Mnemonic Phrase: A New Orientation of Wallets Backup Based on Biometric-Key

A Mnemonic phrase is a set of secret words that correspond one-to-one with the secret key of a user's crypto wallet. If this phrase is lost, the user cannot access the cryptocurrencies. Thus, the user wants to back up the phrase with multiple storage, but the risk of leakage increases. To solve this dilemma, this paper proposes a leakable mnemonic phrase system in which the phrase is encrypted with a secret key generated from the user's biometric information. Since the leakable mnemonic phrase can be decrypted only with the user's biometric information, it can be backed up to various external storage and devices to solve the contradictory problem of keeping the contents of the phrase secret while preventing its loss. In this paper, we also show the results of evaluating the performance of this system by implementing it on an actual biometric authentication device. The encryption/decryption processing time is fast (200 ms), and the system successfully decrypted the mnemonic phrase six months after enrollment.