FPGA based audio watermarking—Covert communication

The rapid growth of internet has greatly facilitated the unauthorized distribution and hacking of digital media, which has become easier due to the availability of processing platforms. Watermarking help us to enforce the intellectual property rights and protect digital media from tampering. There are numerous software based watermarking available and it has attained certain degree of maturity. But hardware based watermarking is still at its infancy. It helps to achieve real time performance by integrating a watermarking chip with existing electronic devices. This paper is an extension of [1]. In [1], the technique was tested only for pulse signal, whereas in this paper FPGA implementation of audio watermarking using chirp spread spectrum (CSS) technique is analyzed with different test patterns and real time audio signal (.wav) and it is observed that the proposed technique provides good imperceptible, robust and low power consumption. Hence this technique helps to achieve covert communication using chirp signal as a secret key between the transmitter and the receiver. The proposed chirp spread spectrum audio watermarking technique is implemented in Vertex 4-XC4VLX25-10FF668 FPGA device. To our knowledge this is the first FPGA based audio watermarking chip, which helps to provide covert communication.