Method and system for enforced biometric authentication

A method for enforced biometric authentication of a user by means of a challenge/response procedure with a mobile station that comprises a display, at least one camera, at least one microphone, at least one loudspeaker and an interface that is connectable to an authentication server via a communications network, the method comprising the steps of

• a) enrolling the user by capturing biometric data of the user by the mobile station, and storing the captured biometric data together with identification data of the user in a database of the authentication server;
• b) authenticating the user, by the authentication server, before performing a transaction by:
• b1) establishing a communication channel between the mobile station and the authentication server;
• b2) transmitting a challenge, by the authentication server, to the mobile station;
• b3) recording, by the mobile station, a response sequence expressed by the user in reply to the challenge and recording simultaneously an ambient response including at least one of;
• ambient optical signals and ambient acoustical signals;
• b4) transmitting, by the mobile station, the recorded response sequence and the recorded ambient signals of the ambient response to the authentication server;
• b5) evaluating, by the authentication server, the recorded response sequence based on related biometric data retrieved from the database and verifying whether the user corresponds to the enrolled user;
• b6) evaluating, by the authentication server, the recorded ambient signals and identifying signal changes within the recorded ambient signals;
• and
• b7) determining, by the authentication server, whether the identified signal changes correspond to a change of the user's response.