A method and associated circuits protect data stored in a secure data circuit of a telecommunication device equipped with a near-field communication (NFC) router, a microcontroller, and the secure data circuit. In the method, each message received with the NFC router is parsed to retrieve a communication pipe identifier and an instruction code. The communication pipe identifier and the instruction code are compared to corresponding information in a filter table. Instruction codes of particular messages that attempt to modify a communication pipe by reassigning one end of the communication pipe from the port of the NFC router to a different circuit are acted upon. These messages are blocked from reaching the secure data circuit when the instruction code is not authorized in the filter table, and these messages are permitted when the instruction code is authorized in the filter table.