a Schematic illustration of an on-dose PUF with a photograph of covert and transparent PUFs attached on the surface of medicines. The PUF device is composed of nothing but proteins from fluorescent proteins and silk to be edible and digestible. The distinct photoluminescent properties of fluorescent proteins in silk provide the parametric support of unique challenge-response pairs. In reaction to an input challenge (Cn), the edible PUF generates its corresponding output response (Rn), resulting in a cryptographic key (Kn). The protein-based PUFs attached on the surface of medicines can be used for on-dose authentication of each individual medicine. b Concept of on-dose authentication. Each individual medicine in a solid oral dosage form (e.g., tablets and capsules) is integrated with an edible PUF device by the pharmaceutical manufacturer. End users (e.g., pharmacists and consumers) can ensure the provenance and validate the medicine by accessing the enrolled digital keys in a secure database (e.g., cloud server). In addition, this edible PUF could be utilized to provide dose information and manufacturer-determined data, including product information (e.g., dosage strength, dose frequency, and expiration date), manufacturing details (e.g., location, date, batch, and lot number), and distribution path (e.g., country, distributor, wholesaler, and chain).