Improving Dynamic Security of the Least Significant Bit Using Block-Based Chaotic Multi-level LSB (BCM-LSB)

Least Significant Bit (LSB) embedding is one of the most common techniques used in audio steganography. LSB audio steganographic techniques have poor dynamic security and are vulnerable to visual and statistical attacks. Therefore, secret information should be disseminated throughout the cover audio to withstand these attacks. To solve this issue, the Block-based Chaotic Multi-level Least Significant Bit (BCM-LSB), which comprises two elements: block generator and rounding mechanism, is proposed. The block generator controls the size and quantity of the block, along with the initial embedding point of the secret information based on a set of stego-keys. In addition, the rounding mechanism ensures that any incomplete embedding process within a block is carried forward to the start of the same block to maximise the BCM-LSB capacity. The proposed method achieves an even distribution of the secret information across the cover audio by utilising these two elements. The results indicate that the BCM-LSB achieved the research objective while maintaining the audio steganography capacity, imperceptibility, and robustness. The segmental SNR (seg-SNR) test indicated that the BCM-LSB avoided graph spikes compared to existing methods. Moreover, the BCM-LSB distributed the error fairly throughout the stego-file compared to other existing methods. The BCM-LSB achieved high dynamic security as all variations successfully distributed the secret information throughout the cover audio.