A Dual-Protection Method for 3D Object Security and Copyright: Watermark Embedding During Decryption

With advancements in the computer industry, 3D objects are now widely used in various applications, including game development, animation production, and industrial design. This growing adoption has increased the need for effective content security and copyright protection for 3D objects. However, existing encryption and watermarking techniques often operate independently, leading to low efficiency and weak coupling between security and copyright protection. To address these gaps, this paper presents a novel method that integrates watermark embedding into the 3D object decryption process, simultaneously ensuring content security and copyright protection. Specifically, a Look-Up Table (LUT)-based encryption method is employed to secure 3D object data, while a Spread Transform Dither Modulation (ST-DM)-based watermarking method is used to embed user-specific identity information during decryption. Unlike conventional approaches that apply encryption and watermarking separately, the proposed method enables efficient 3D object sharing, as the owner only needs to encrypt the object once, regardless of the number of authorized users. The encrypted model can then be distributed securely via multicast and caching. Decryption with personalized keys produces distinct watermarked 3D objects, allowing for reliable traceability of unauthorized redistribution. Experimental results and theoretical evaluations demonstrate that the proposed method delivers satisfactory visual quality, efficiency, robustness, and security.