Abstract: A device and method for applying and retaining a data carrier to a living body for providing identification of the body with respect to a reference group wherein the body's external nail surface structure, the method comprising selecting a carrier suitable for attachment to the nail surface, modifying the carrier to include a unique data format and attaching the carrier at the nail surface. The data carrier comprises a thin, substantially flat carrier suitable for attachment to the nail surface and a unique data format applied to the carrier adapting the same for repeated detection. The device and method are adaptable for use within identification systems such as hospital patient identification, clinical testing and security access control environments.