Secure Analysis of Optical Steganography with Spectral Signature Measurement

The threat and defend model of optical steganography based on amplified spontaneous emission noise is experimentally demonstrated. Although the optical delays in a steganography system generate large key space to hide and recover the stealth signals, delays in interferometer introduce spectral fringes that can be identified by the coherent detection attack and thus expose the stealth channel. To defend such attacks, the spectral fringes are removed by with stealth data rate that is beyond the response speed of the coherent detection. Experimental results show that the spectral signatures can be protected by both wideband property of spontaneous emission noise and setting up the optical delays and data rate within the secure range. Such defending method can guide the design of a secure optical steganography system.