The disclosure relates to a mobile terminal for capturing the biometric data (BD) of a user. The terminal comprises: a data storage unit having a credential (C); an authentication module; a sensor for capturing the bio-metric data of the user; a control unit that is configured to capture the bio-metric data (BD) of the user automatically or semi-automatically by means of a sensor only upon successful, reciprocal authentication of the user and the mobile terminal; a test unit for automatic testing of the authenticity of the biometric data captured. The control unit is configured to store the biometric data captured in the data storage unit in protected form only then, when the biometric data captured is authentic according to the test. The authentication module (304) is configured to authenticate an operator to the mobile terminal by means of additional authentication data (AD3) attributed to the operator. The control unit is configured to enable the readout of the biometric data that is stored in protected form for transmission of the biometric data read to a security document, only if the operator has been authenticated successfully.