In an example, a non-transitory machine-readable storage medium includes stored instructions. The store instructions, when executed by one or more processors, cause the one or more processors to: receive a unique identifier of a tagged physical good; receive a public key stored in a Non-Fungible Token (NFT) corresponding to the unique identifier; encrypt a first passphrase using the public key to obtain an encrypted passphrase; compare a second passphrase to the first passphrase; and generate an output indication in response to comparing the second passphrase to the first passphrase. The second passphrase is generated by decrypting the encrypted passphrase using a private key stored on an electronic tag device embedded in the tagged physical good.