Style as Cover: Deep Image Steganography via Stylized Transmission
Authors: Qi Li, Jidong Yang, Huaike Yu, Chunpeng Wang, Suo Gao, Herbert Ho-Ching Iu, Yuantian Miao, Bin Ma, Xiao Chen
Organizations: Key Laboratory of Computing Power Network and Information Security, Ministry of Education, Shandong Computer Science Center, and Shandong Provincial Key Laboratory of Industrial Network and Information System Security, Shandong Fundamental Research Center for Computer Science, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China · School of Information Science and Engineering, Dalian Polytechnic University, Dalian 116034, China · School of Electrical, Electronic and Computer Engineering, The University of Western Australia, Perth, WA 6009, Australia · School of Computer and Information Sciences, The University of Newcastle, College of Engineering, Science and Environment, Callaghan, NSW 2308, Australia
Image steganography hides secret message within normal images, with most existing works relying on cover-preserving transmission. However, such a paradigm becomes vulnerable once the original cover is exposed or can be reliably approximated. In this paper, we propose StyleStegaNet, a stylized image hiding framework that replaces cover matching with style-concealment transmission. Instead of transmitting a cover-like stego image, StyleStegaNet generates stylized stego images conditioned on publicly available style references, redefining steganography invisibility from cover-preserving concealment to behavior-level camouflage based on style transformation. Such a setting poses a substantial challenge to reliable secret recovery, since neural stylization can significantly alter the feature statistics exploited by deep hiding methods. To address this challenge, StyleStegaNet decouples the overall task into four coordinated stages: stego generation, stylized transmission, structure-preserving reconstruction, and secret recovery. Moreover, StyleStegaNet is optimized with a progressive three-stage training strategy, in which wavelet-domain constraints and perceptual supervision guide the recoverable information toward structural representations. We further provide an analysis showing that secret recoverability is largely restricted to the normalized structural subspace, offering a mechanistic explanation for why directly stylized baselines fail and why a reconstruction-guided recovery path is necessary. Extensive experiments on DIV2K and MS-COCO datasets demonstrate the effectiveness of StyleStegaNet. And few-shot image steganalysis with two deep detectors further shows detection accuracy near random guessing, approximately 51%.
Figures & tables
Figure 1: Comparison with conventional image hiding. StyleStegaNet transmits a recoverable stylized stego image instead of a stego image close to the cover.
Notation
Description
S
Secret image
C
Cover image
Y
Style image
X
Stego image
T
Stylized stego image transmitted by the sender
X′
Recovered stego image
Table 1: Summary of Notation.
Figure 3
Figure 3: StyleStego generation at the sender: a learnable steganographic encoder Eθ followed by a frozen stylization network Fϕ .
Figure 4: Architecture of the RevStego network Rψ and secret decoder Dη .
Stage
Objective
Evaluated pair
PSNR(dB)
Stage 1
LS1
(X,C)
38.63
Stage 2
LS2
(X′,X)
32.78
Stage 3
LS3
(S′,S)
28.49
Table 2: DIV2K training-stage completion PSNR of StyleStegaNet.
Table 3: Stylized-transmission stress test on (S′,S) . Conventional baselines use stego → stylization → original decoder.
Figure 5: Qualitative comparison under stylized transmission. Conventional reveal paths degrade after stylization, while StyleStegaNet remains recoverable.
Method
SiaStegNet
SRNet
Avg.
N=100
Avg.
N=100
StyleStegaNet
51.00
50.75
51.50
51.50
PUSNet
54.65
57.75
62.23
70.50
BalujaNet
65.38
74.50
77.17
81.75
HiDDeN
74.12
93.25
61.83
62.50
HiNet
73.03
94.50
76.42
93.00
Table 4: Deep steganalysis accuracy (%) of the SiaStegNet [ 41 ] and SRNet [ 8 ] detectors. Lower is better; 50% is random guessing.
Figure 6: Few-shot steganalysis accuracy with the SiaStegNet [ 41 ] and SRNet [ 8 ] detectors. The dashed line marks random guessing; lower accuracy indicates lower detectability.
Figure 7: Magnified residual maps under stylized transmission ( 10× ). In this cover-known diagnostic, StyleStegaNet residuals do not visually expose the secret structure; this is not a guarantee against adaptive attacks.
DIV2K: (S′,S)
Methods
PSNR ↑
SSIM ↑
APD ↓
RMSE ↓
Full StyleStegaNet
27.02
0.8830
7.71
12.07
Context refiner
24.91
0.8144
9.90
15.35
w/o secret refinement
23.83
0.7663
11.42
17.29
w/o high-frequency loss
24.86
0.8065
9.96
15.44
Late secret refinement
24.72
0.8056
10.14
15.69
Table 5: Stage 3 ablation on (S′,S) . Arrows indicate the preferred direction.
Zhejiang Provincial Key Laboratory for Sensitive Data Security Protection and Confidentiality Management, Hangzhou Dianzi University, Hangzhou 310018, China · Arcvideo Technology, Hangzhou 310018, China