The proliferation of hyper-realistic images from Latent Diffusion Models (LDMs) demands robust watermarking, yet existing post-hoc methods are prohibitively slow due to iterative optimization or inversion processes. We introduce PhaseMark, a single-shot, optimization-free framework that directly modulates the phase in the VAE latent frequency domain. This approach makes PhaseMark thousands of times faster than optimization-based techniques while achieving state-of-the-art resilience against severe attacks, including regeneration, without degrading image quality. We analyze four modulation variants, revealing a clear performance-quality trade-off. PhaseMark demonstrates a new paradigm where efficient, resilient watermarking is achieved by exploiting intrinsic latent properties.

翻译：随着潜在扩散模型生成超真实图像的普及，鲁棒水印技术需求日益迫切，但现有后置方法因依赖迭代优化或反演过程而速度缓慢。本文提出PhaseMark，一种单次执行、无需优化的框架，直接在VAE潜在频率域中调制相位。该方法使PhaseMark比基于优化的技术快数千倍，同时在保持图像质量的前提下，对包括再生攻击在内的严重攻击实现了最先进的鲁棒性。我们分析了四种调制变体，揭示了明确的性能-质量权衡关系。PhaseMark展示了一种新范式：通过利用潜在空间的内在特性，实现高效且鲁棒的水印嵌入。