High Capacity and Reversible Steganographic Technique with Authentication Capability

This paper proposes a high capacity and reversible DCT-based steganographic technique with authentication capability for 8-bit grayscale general and medical images. The technique obtains 64 DCT coefficients by performing DCT on an (8 × 8) cover image block and only uses selected AC coefficients to hide the secret message. The proposed scheme embeds a fragile watermark using LSB substitution in the selected pixel of the (8 × 8) stego image block to verify the stego image's authenticity. The proposed scheme’s performance is evaluated based on payload, imperceptibility, fragility, and image authentication analyses. Simulation results confirm that the steganographic technique is reversible, supports a good payload, and produces high quality watermarked images. The proposed technique outperforms state-of-the-art techniques in embedding capacity while maintaining good image quality. The fragility and authentication analysis confirm that our proposed scheme is fragile in nature and can detect various image processing and geometrical attacks. Our scheme can verify the stego image’s authenticity and is also capable of detecting whether the message has been corrupted.