Private key updating method and device based on blockchain

The invention discloses a private key updating method and device based on a blockchain, and the method comprises the steps: obtaining a first private key box corresponding to a user identifier from the blockchain according to the user identifier; collecting a first biological feature input by the user, and extracting first feature data through a biological feature extraction module; determining an initial private key corresponding to the user identifier according to the first feature data and the first private key box, and generating a digital signature according to the initial private key; generating an update private key and an update public key through a first preset algorithm, and calculating a hash value of the update private key; collecting a second biological feature input by the user, and extracting second feature data through a biological feature extraction module; generating a second private key box corresponding to the user identifier according to the update private key and the second feature data;