A portable data carrier comprises a communication means and a memory with a biometric template which is intended to be compared with a biometric sample for identity check. The biometric template is divided into a private part which is adapted to be exclusively used in the portable data carrier and a public part which is adapted to be transferred, with the aid of the communication means, to an external processing unit and be used therein. Moreover, a processing unit for use in biometric identity check is described, comprising a processor and a communication means. The communication means is adapted to receive a biometric sample and a public part of a biometric template, the processor is adapted to compare the received public part of the template with the biometric sample, and the communication means is further adapted to transfer, when a comparison criterion has been satisfied, at least part of the biometric sample to the portable data carrier for further comparison on the data carrier. A method for recording a biometric template and performing a biometric identity check is also described.