Abstract: A method performed by a device for protecting content by using biometric information is provided. The content protection method includes displaying, by the device, identification information of encrypted content, receiving, by the device, a user input of selecting the encrypted content, controlling, by the device, according to the reception of the user input of selecting the encrypted content, a sensor to obtain image information of a user's body part, calculating, by the device, feature information of the user's body part from the obtained image information, reproducing, by the device, a crypto key based on the calculated feature information of the user's body part and hint information stored in correspondence to the encrypted content, decrypting, by the device, the encrypted content based on the reproduced crypto key, and displaying, by the device, the encrypted content according to the decryption of the encrypted content.

Abstract: A user authentication method, by which a device authenticates a user, is provided. The user authentication method includes performing basic authentication based on a received user input, obtaining behavioral characteristics with which the user uses the device, and when the user has passed the basic authentication, performing additional authentication for the user by applying the obtained behavioral characteristics to a first learning model, wherein the first learning model is a model trained to perform the additional authentication for the user, based on at least one of a plurality of behavioral characteristics of an authenticated user, the behavioral characteristics being accumulated in the device.