This paper proposes a novel fingerprinting method by applying the controlled non-linearities of RF amplifiers in compression mode to generate robust signal signatures. By analyzing the distinct distortion patterns and harmonic content produced under compression, we define a signaling mechanism helping to generate a robust fingerprinting mechanism. Our approach presents an ability to generate confusion in eavesdroppers so ensuring high robustness and resilience against passive and active attacks. Numerical results demonstrate the consistency and robustness of the signal signatures. This method not only enhances security by integrating physical-layer properties, but may contribute to reduce the computational burden of traditional cryptographic techniques. Our findings indicate that using amplifier non-linearities for fingerprinting significantly improves the security and efficiency of wireless communication systems.