A method for identifying and authenticating a user in order to grant the user access to a secured area in an IP network, in particular to confidential data and/or services, the method comprising at least the following steps: - receiving, by means of an audio-capable device, a voice input spoken by the user into the audio-capable device, - transforming the received voice input, by means of the audio-capable device, into a sequence of audio fragments, wherein the respective audio fragments have a predetermined format and the sequence of the audio fragments forms a voiceprint, - transmitting the audio fragments to a speech processing platform, wherein the respective audio fragments are transmitted with a predetermined audio transmission length in a respective IP packet, - after receipt of the respective audio fragments in the voice processing platform, sequentially according to the sequence of audio fragments for each received audio fragment: comparing (24, 34) the respective audio fragment with a set of reference voiceprints stored in a reference database potentially matching the voiceprint to find a matching reference voiceprint, calculating a confidence value for each stored potentially matching reference voiceprint with respect to the respective audio fragment, discarding (25, 35) each stored potentially matching reference voiceprint whose confidence value is below a given threshold from the set of potentially matching reference voiceprints, and recursively comparing (26, 36) the respective subsequent audio fragment in the sequence only with the set of respective remaining potentially matching reference voiceprints from the reference database until only one reference voiceprint remains in the set as possible matching reference voiceprint. - receiving, by means of an audio-capable device, a voice input spoken by the user into the audio-capable device, - transforming the received voice input, by means of the audio-capable device, into a sequence of audio fragments, wherein the respective audio fragments have a predetermined format and the sequence of the audio fragments forms a voiceprint, - transmitting the audio fragments to a speech processing platform, wherein the respective audio fragments are transmitted with a predetermined audio transmission length in a respective IP packet, - after receipt of the respective audio fragments in the voice processing platform, sequentially according to the sequence of audio fragments for each received audio fragment: comparing (24, 34) the respective audio fragment with a set of reference voiceprints stored in a reference database potentially matching the voiceprint to find a matching reference voiceprint, calculating a confidence value for each stored potentially matching reference voiceprint with respect to the respective audio fragment, discarding (25, 35) each stored potentially matching reference voiceprint whose confidence value is below a given threshold from the set of potentially matching reference voiceprints, and recursively comparing (26, 36) the respective subsequent audio fragment in the sequence only with the set of respective remaining potentially matching reference voiceprints from the reference database until only one reference voiceprint remains in the set as possible matching reference voiceprint.