Enhancing Imperceptibility: Zero-width Character-based Text Steganography for Preserving Message Privacy

Methods: A text steganography method is proposed that uses eight zero-width characters (ZWCs) to embed secret messages in the cover text. The proposed method also treats every character in the cover text as a potential embedding location. With eight embedding choices and bit encoding based on embedding locations, more bits can be hidden with fewer insertions in cover text.

Results: Experimental results confirm that the proposed method embeds a greater number of bits per insertion of ZWC in the cover text. It also requires a smaller number of insertions to embed secret messages of comparable length. Consequently, the proposed method achieves higher embedding capacity and better imperceptibility compared to existing text steganography methods.

Conclusion: The proposed method presents a substantial improvement in text steganography by increasing embedding capacity per distortion and preserving high similarity between cover and stegotext, thus enabling more secure covert communication.