## 3 Experimental Results and Analysis
### A Comparison with the Current State-of-the-Art Works  
Table 10 compares our algorithm with the current state-of-the-art works presented for HDR data hiding/HDR image encryption. While most of the schemes were based on RGBE format, only two algorithms adopted the OpenEXR format. The embedding rates for these schemes vary ranging from less than 1.0 bpp to as large as 20.0 bpp. Our algorithm performs better than most competitors except [PERSON] et al. 's work [16]. With regard to the quality of tone-mapped image, our scheme produces a tone-mapped stego image with moderate PSNR (50.49 dB), which is inferior to [16,19] but superior to [17,18]. Note that the PSNR depends not only on the tone mapping algorithm adopted but also on the number of concealed secret messages. Our algorithm is the first constructive data hiding approach that can adaptively convey secret messages, encrypt the stego HDR image, and offer the prediction ability. Our scheme conceals more secret messages in pixels with low luminance. In addition, the user has flexibility to embed in a high payload with more distortion allowed, or to conceal a low \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline
**Algorithm** & **Proposed** & 12M & 1 PM & 1 PM & 1 PM1 & 1 PM1 & 1 PM1 & 1 PM1 & 1 PM1 & 1 PM1 \\ \hline
**Year** & 2022 & 2022 & 2022 & 2023 & 2019 & 2027 & 2016 & 2022 & 2011 & 201 & 209 \\ \hline
**Front** & OpenEXR & 860E & 860E & 860E & 860E & 860E & 860E & 860E & 860E & 860E \\ \hline
**ES (ppd)** & 7.30-529 & 6.19-7.03 & 1.07-2.34 & 0.480-2.320 & 1.90-2.43 & 2.435-0.002 & 0.1394-0.1472 & 0.1340-0.1273 & 0.1256-0.1258 & 80.0 & 504-570 \\ \hline
**PSNR** & 32.60-51-50 & N.A. & 61.39-55.66 & 5.65-51.77 & 35.86-39.36 & 45.12-42.02 & N.A. & N.A. & N.A. & 30.67-370 & 200-400 \\ \hline
**SSIM** & 0.9943-1.000 & N.A. & 0.9904-0.9999 & 0.8542-0.9964 & N.A. & 0.7527-0.999 & N.A. & N.A. & N.A. & N.A. & N.A. \\ \hline
**Energizing** & **Yes** & **Yes** & **No** & **No** & **No** & **No** & **No** & **No** & **No** & **No** \\ \hline
**NIST Test** & **Yes** & **No** & **No** & **No** & **No** & **No** & **No** & **No** & **No** & **No** \\ \hline
**Adaptive** & **Yes** & **No** & **No** & **No** & **No** & **No** & **No** & **No** & **No** & **No** \\ \hline
**Position** & **Yes** & **No** & **No** & **No** & **No** & **No** & **No** & **No** & **No** & **No** \\ \hline
**User Reg** & **Yes** & **No** & **No** & **No** & **No** & **No** & **No** & **No** & **No** & **No** \\ \hline
**Conductivity** & **Yes** & **No** & **No** & **No** & **No** & **No** & **No** & **No** & **No** & **No** \\ \hline
**Evaluation** & Six Manics & Visual & - & - & - & - & - & - & - & - & - \\ \hline
**Security** & High & Low & - & - & - & - & - & - & - & - & - \\ \hline \hline \end{tabular}
\end{table} 
Table 10: A comparison of our scheme with the current state-of-the-art works. Figure 12: Key sensitivity test using the image, “rosette,” where the secret key \(K_{2}\) is one-bit different from the secret key \(K_{1}\); (**a**) the original stego image \(I_{S}\); (**b**) using \(K_{1}\) to cipher \(I_{S}\) and producing \(EI_{S1}\); (**c**) deciphering \(EI_{S1}\) by \(K_{1}\) to produce the genuine \(I_{S}\); (**d**) using \(K_{2}\) to cipher \(I_{S}\) and producing \(EI_{S2}\); (**e**) NPCR and UACI results for the image pair \((EI_{S1},EI_{S2})\); (**f**) deciphering \(EI_{S1}\) by the incorrect key, \(K_{2}\), and producing a noisy image. payload in exchange for high image quality. In this paper, the user demand embedding rate is set to be 7.3 bpp, but our scheme can offer the embedding rate to reach 9.29 bpp, larger than most of our competitors, or alternatively to reduce to 4.3 bpp or even lower. Nevertheless, thanks to the adaptive embedding and the optimal base, the stego image produced by our scheme maintains high image quality. Furthermore, [PERSON] et al. [20] and our algorithm investigated the HDR image encryption. However, we propose six metrics to evaluate the security analysis completely rather than providing only visual perception.