A secure apparatus, system, device and method for coding surface acoustic wave identification tags and sensors to enable unique sensor operation and identification for a multi-sensor environment. In an embodiment, a pseudo noise sequence is applied to the orthogonally coded signal for increased security. An orthogonal frequency coding technique is applied to the SAW tag using periodic reflector gratings for responding to an orthogonal interrogation signal to transmit the sensor identification and sensed data. A transceiver interrogates the sensor with a stepped chirp corresponding to the orthogonal frequency coded chip frequency response, receives a response from the SAW device, applies an oppositely stepped chirp to the response and then uses matched filtering to produce a compressed pulse. The orthogonal frequency coding technique has an inherent advantage of processing gain, code division multiple access, spread spectrum and security.