Table 2:
Existing steganographic techniques: contributions and limitations
| S. No. | Reference | Contribution | Limitation |
|---|---|---|---|
| 1 | [3] | Multilevel encryption + blue-channel block shuffling; near-zero MSE, SSIM | Vulnerable to geometric distortions and lossy compression. |
| 2 | [2] | LSB + PVD + multitier encryption; PSNR > 30 dB, SSIM ≈1 | Trade-offs between payload, imperceptibility, and robustness not fully explored. |
| 3 | [13] | Center-pixel offset + pseudorandom sequence; high PSNR, low cost | Untested against advanced steganalysis. |
| 4 | [8] | LoG + Canny hybrid in wavelet domain; high capacity, strong imperceptibility | Limited payload when edges are sparse. |
| 5 | [10] | Survey of chaotic and randomized | Increased computational complexity. |
| 6 | [14] | LSB strategies; improved stealth MSB matching + LSB substitution; up to 6 bits/pixel, minimal distortion | Resilience under compression not evaluated. |
| 7 | [15] | Distinction grade value method; robust against noise | Lacks new experimental validation. |
| 8 | [16] | Embedding in high-variance regions; PSNR/SSIM gains | Computationally intensive for real-time use. |

Figure 1:
Proposed diagram for data hiding.

Figure 2:
Proposed diagram for data extraction.

Figure 3:
Histogram analysis of cover and stego-image.
Table 3:
Evaluation metrics for stego-image quality and performance
| Metric | Description | Role |
|---|---|---|
| Capacity (m) | The total number of bits that can be embedded into the cover image; mathematically m = |M|, where M is the message bit-stream. | Defines payload limit and governs the trade-off between embedding rate and imperceptibility. |
| MSE | MSE between cover and stego images: | Quantifies raw embedding noise energy; lower MSE indicates smaller average pixel perturbations. |
| PSNR | PSNR, computed from MSE: | Transforms MSE into a more interpretable logarithmic scale; values > 40 dB typically imply perceptual losslessness. |
| SSIM | Structural Similarity Index, measuring perceptual quality: where μ, σ, and σCS denote means, variances, and covariance, respectively. | Assesses structural and contrast preservation; high SSIM (≈1) ensures imperceptibility and resists structure-based attacks. |
| Embedding time (Te) | Total time for the embedding operation:; where Tpre is preprocessing (e.g., edge detection) and Tembed is bit embedding. | Measures computational efficiency; critical for real-time or large-scale applications. |
| Histogram analysis | Comparison of pixel-intensity histograms between cover and stego images to detect distribution shifts. | Detects statistical anomalies introduced by embedding; ensures stego-images remain statistically indistinguishable from covers. |
Algorithm 1:
Proposed algorithm
|
Table 4:
Evaluation metrics of different cover and message images
| S. No. | Cover image | Message image | Capacity (BPP) | PSNR (dB) | SSIM | Embedding time (s) |
|---|---|---|---|---|---|---|
| 1 | Moon | Lena | 0.0358 | 65.60 | 1.0000 | 0.2441 |
| 2 | Barb | Lena | 0.0524 | 63.95 | 1.0000 | 0.0613 |
| 3 | Bluesea | Lena | 0.0225 | 67.63 | 1.0000 | 0.1500 |
| 4 | Boat | Lena | 0.0288 | 66.82 | 1.0000 | 0.0126 |
| 5 | House | Lena | 0.0395 | 65.19 | 1.0000 | 0.2096 |
| 6 | Loin | Lena | 0.0355 | 65.65 | 1.0000 | 0.0286 |
| 7 | Mandrill | Lena | 0.0394 | 65.18 | 1.0000 | 0.0144 |
| 8 | Nature | Lena | 0.0384 | 65.30 | 1.0000 | 0.3303 |
| 9 | River | Lena | 0.0440 | 64.69 | 1.0000 | 0.0690 |
| 10 | Water | Lena | 0.0488 | 64.25 | 1.0000 | 0.2434 |
Table 6:
Performance comparison of embedding strategies
| Embedding strategy | Average PSNR (dB) | Average SSIM | Embedding rate (BPP) |
|---|---|---|---|
| Edge-guided embedding | 65.43 | 1.000 | 0.0385 |
| Global embedding | 62.99 | 0.962 | 0.0568 |
Table 7:
Comparison of PSNR and SSIM with recent LSB-based methods
| No. | Reference | Baseline PSNR (dB) | Baseline SSIM | Our PSNR (dB) | Our SSIM |
|---|---|---|---|---|---|
| 1 | Ali et al. [14] | 63.95 | 0.965 | 65.60 | 1.0000 |
| 2 | Chaudhary and Sharma [34] | 54.32 | 0.943 | 63.95 | 1.0000 |
| 3 | Mali and Dongre [12] | 65.19 | 0.972 | 65.30 | 1.0000 |
| 4 | Mukherjee and Sanyal [36] | 52.87 | 0.930 | 66.82 | 1.0000 |
| 5 | Rahman et al. [3] | 52.14 | 0.968 | 65.19 | 1.0000 |
| 6 | Zhang et al. [7] | 65.30 | 0.970 | 65.65 | 1.0000 |
| 7 | Kaur and Singh [18] | 64.69 | 0.960 | 65.18 | 1.0000 |
| 8 | Wu and Li [37] | 65.00 | 0.975 | 65.30 | 1.0000 |
| 9 | Wang and Zhang [25] | 66.00 | 0.978 | 67.63 | 1.0000 |
