Abstract: A system and method for authentication of objects, which includes directing a laser beam onto a surface of an object to induce a thermoelastic excitation in bulk material of the object without altering the surface of the object, wherein the laser beam is pulsed. A surface ultrasonic wave at the surface of the object caused by the thermoelastic excitation is detected using a detector. A detection signal is generated using the detected surface ultrasonic wave. Digital data is generated using the detection signal. Authenticity of the object is determined by comparing the digital data and reference data stored in a database.