3D Gaussian Splatting (3DGS) has already become the emerging research focus in the fields of 3D scene reconstruction and novel view synthesis. Given that training a 3DGS requires a significant amount of time and computational cost, it is crucial to protect the copyright, integrity, and privacy of such 3D assets. Steganography, as a crucial technique for encrypted transmission and copyright protection, has been extensively studied. However, it still lacks profound exploration targeted at 3DGS. Unlike its predecessor NeRF, 3DGS possesses two distinct features: 1) explicit 3D representation; and 2) real-time rendering speeds. These characteristics result in the 3DGS point cloud files being public and transparent, with each Gaussian point having a clear physical significance. Therefore, ensuring the security and fidelity of the original 3D scene while embedding information into the 3DGS point cloud files is an extremely challenging task. To solve the above-mentioned issue, we first propose a steganography framework for 3DGS, dubbed GS-Hider, which can embed 3D scenes and images into original GS point clouds in an invisible manner and accurately extract the hidden messages. Specifically, we design a coupled secured feature attribute to replace the original 3DGS's spherical harmonics coefficients and then use a scene decoder and a message decoder to disentangle the original RGB scene and the hidden message. Extensive experiments demonstrated that the proposed GS-Hider can effectively conceal multimodal messages without compromising rendering quality and possesses exceptional security, robustness, capacity, and flexibility. Our project is available at: https://xuanyuzhang21.github.io/project/gshider.

翻译：3D高斯泼溅（3DGS）已成为三维场景重建与新视角合成领域的新兴研究热点。鉴于训练3DGS需要大量时间与计算成本，保护此类三维资产的版权、完整性与隐私至关重要。隐写术作为加密传输与版权保护的关键技术，已得到广泛研究，但针对3DGS的深入探索仍显不足。与先前技术NeRF不同，3DGS具备两大显著特征：1）显式的三维表示；2）实时渲染速度。这些特性使得3DGS点云文件公开透明，每个高斯点均具有明确的物理意义。因此，在向3DGS点云文件中嵌入信息的同时，确保原始三维场景的安全性与保真度成为极具挑战性的任务。为解决上述问题，我们首次提出面向3DGS的隐写框架GS-Hider，能够以不可见方式将三维场景与图像嵌入原始GS点云，并精确提取隐藏信息。具体而言，我们设计了耦合安全特征属性以替代原始3DGS的球谐系数，继而通过场景解码器与信息解码器分离原始RGB场景与隐藏信息。大量实验表明，所提出的GS-Hider能在不影响渲染质量的前提下有效隐藏多模态信息，并具备卓越的安全性、鲁棒性、容量与灵活性。项目地址：https://xuanyuzhang21.github.io/project/gshider。