Abstract: A method of unambiguous identification and authentication of products for the purpose of better recognition of product forgeries and controlling product piracy, including applying to/into the product an identification substance admixture which contains paramagnetic phases or identifying a product which contains an identification substance admixture containing paramagnetic phases and has an ESR fingerprint spectrum that permits unambiguous identification of the product. Such an ESR fingerprint spectrum is easily measurable, but can be copied or forged only with difficulty. The method relates to an individualizable “femto tag” for femto ledgers and forms an important interface for what are known as “Internet of Things” (IOT).