There is described a computer-implemented method for authorizing a user device, comprising: use of a processor for receiving an extracted identifier transmitted by a secondary device to be authorized over a telecommunication network, the extracted identifier being previously extracted by the secondary device to be authorized from an acoustic signal generated by an authorized main device, the acoustic signal corresponding to a transmitted audio signal received by the authorized main device and having a reference identifier embedded therein; use of the processor for validating the received identifier; and upon successful validation, use of the processor for transmitting an authorization confirmation to the secondary device.