Physical Unclonable Functions (PUFs) for authentication can be implemented in a variety of electronic devices including FPGAs, RFIDs, and ASICs. In some implementations, challenge-response pairs corresponding to individual PUFs can be enrolled and used to determine authentication data, which may be managed in a database. Later when a target object with a PUF is intended to be authenticated a set (or subset) of challenges are applied to each PUF device to authenticate it and thus distinguish it from others. In some examples, authentication is achieved without requiring complex cryptography circuitry implemented on the device. Furthermore, an authentication station does not necessarily have to be in communication with an authority holding the authentication data when a particular device is to be authenticated.