利用部分 C2PA 溯源信息提升图像取证检测性能
Enhanced image forensics through partial C2PA-based provenance information
一篇讲图像取证的论文：图像带部分 C2PA 溯源时，怎么把这段可信信息用来增强合成图检测，思路挺少见。
arXiv 论文研究带部分 Content Credentials（CCs）的图像取证问题：已有图像经受信任的 C2PA 软件处理后，CC 只记录最后一步操作，此前来源未知。论文提出两步策略：先通过结构分析重建最后签名者执行的操作，再用重建结果适配取证检测器，缓解分布偏移。作者在商业 C2PA 软件生成的部分 CC 上验证了操作重建的可行性。在合成图像检测任务的案例中，该策略显著提升了 state-of-the-art 检测器对经 C2PA 软件后处理的生成图像的识别效果。
Enhanced image forensics through partial C2PA-based provenance information
Cryptographically verifiable C2PA-based Content Credentials (CCs) can be attached to freshly acquired or generated digital images but also to already existing ones with no previous provenance information, for instance after processing through trusted C2PA-enabled software tools. The latter case leads to images with so-called partial CCs, which capture only the last operations applied, while prior provenance remains unknown and can be investigated through signal forensics. This paper addresses the forensic analysis of such images, highlighting the opportunity to leverage the partial CCs as additional trusted knowledge to adapt forensic detectors towards the statistical characteristics of the image under analysis and mitigate potential distribution shifts. To this end, a two-step strategy is envisioned: (i) reconstructing the operations applied by the last signer through a structural analysis of the partial CCs; (ii) exploiting the obtained reconstruction to enhance the forensic detector of the analyst through an adaptation process. An empirical analysis on partial CCs produced by commercial C2PA-enabled software tools through different editing operations is carried out, providing evidence on the feasibility of the reconstruction in practical cases. An experimental case study on the forensic task of synthetic image detection is then presented, showing that the proposed strategy can significantly enhance the performance of state-of-the-art detectors on test images that are postprocessed via C2PA-enabled software tools after being generated/acquired.
