A device includes a near field communication (NFC) circuit that is configured and arranged to communicate data with external devices. An internal communication circuit communicates data over a microprocessor bus. A secure memory circuit stores an identifier that is unalterable in the secure memory circuit. Logic circuitry performs a secure transaction protocol. The transaction protocol includes determining whether a communication, received by the NFC circuit, is addressed to the secure memory circuit; sending, in response to determining that the communication is addressed to the secure memory circuit, the communication to the memory circuit; sending, in response to determining that the communication is not addressed to the secure memory circuit, the communication to the microprocessor bus; and transmitting data, received from both the NFC circuit and the secure memory circuit, to the NFC circuit, the transmitted data including the identifier value and configured for communication with external devices using NFC.