Abstract: The disclosure generally relates to methods and apparatuses for user authentication. According to embodiments of the present invention, authentication-related information may be encoded in an image such as a QR code. By communicating and decoding such image information and other authentication information between one or more devices of the user and an authentication server, the authentication server may perform an effective authentication to the user and his/her device. In the meantime, it is possible to avoid the risk of invalid authentication due to the disclosure of the password. Embodiments of the present invention may be used in combination with the existing static password and/or dynamic password authentication and thus they have a good compatibility.