Digital method for authentication of a person by comparing a current voice profile with a previously stored initial voice profile, wherein to determine the relevant voice profile the person speaks at least one speech sample into the system, this speech sample is conveyed to a voice-profile calculation unit and thereby, on the basis of a prespecified voice-profile algorithm, the voice profile is calculated, such that the overall size of the speech sample and/or parameters of its evaluation to determine the relevant voice profile are established dynamically and automatically as the sample is spoken, in response to the result of an evaluation of a first partial speech sample.