非对称相位编码视频水印
Asymmetric Phase Coding Video Watermarking
- Phi Lab（斐实验室）
- University of California, Berkeley（加利福尼亚大学伯克利分校）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
提出一种非对称相位编码视频水印，无需训练，通过嵌入Ed25519签名实现无共享密钥的离线验证，在真实视频集上验证准确率达99.3%，抗H.264重编码和缩放攻击性能优异。
AI中文摘要：
现有视频水印系统是对称的：能验证水印的一方拥有提取器权重或生成器密钥，因此也能嵌入水印。基准测试证实了这一点，报告称白盒伪造可击败所有被评估的方法。我们提出一种无需训练的视频水印，它消除了共享密钥。签名者将完整的Ed25519签名嵌入色度平面的相位谱中；任何持有32字节公钥和每视频公共元数据的一方都可离线验证，无需模型、注册表或网络。有效载荷为1024位带纠错的签名消息，比常见的学习型有效载荷高一个数量级，由三个设计元素承载：一种游程时间布局，其解码器通过相关性识别有效载荷组且从不读取帧索引；一种无有效载荷的搜索，可从载体本身恢复缩放、旋转和平移；一种闭环签名过程，通过不变的公共验证器自验证来选择每个视频的嵌入强度。在1000个未整理的真实视频片段上，该系统为99.3%的语料库提供可验证签名，且在1000次尝试中零次接受错误公钥。一种感知攻击的接受门产生的嵌入可100%抵御H.264重编码，在门控片段上50%缩放时抵御率达97.4%。该签名还可通过真实显示与捕获循环验证，这是已发表评估中缺失的一个维度。
英文摘要：
Existing video watermarking systems are symmetric: the party that can verify a mark holds the extractor weights or generator secret and can therefore also embed one. Benchmarks confirm the consequence, reporting that white-box forgery defeats all evaluated methods. We present a training-free video watermark that removes the shared secret. The signer embeds a complete Ed25519 signature into the phase spectrum of the chroma plane; any party holding the 32-byte public key and public per-video metadata verifies offline, with no model, no registry, and no network. The payload, 1024 bits of signed message with error correction, is an order of magnitude above common learned payloads and is carried by three design elements: a run-length temporal layout whose decoder identifies payload groups by correlation and never reads a frame index, a payload-free search that recovers scale, rotation, and translation from the carrier itself, and a closed-loop signing procedure that selects each video's embedding strength by self-verification through the unchanged public verifier. On 1000 uncurated real-world clips the system ships a verifying signature for 99.3% of the corpus and accepts a wrong public key zero times in 1000 attempts. An attack-aware acceptance gate yields embeddings that survive H.264 re-encoding at 100% and 50% rescaling at 97.4% on gated clips. The signature also verifies through a real display and capture loop, an axis absent from published evaluations.
