# Combating Fake News with Cryptography in Quantum Era with Post-Quantum Verifiable Image Proofs
## 2 C2 PA and Image Editing  
To contextualize our cryptographic solution, we first examine an existing standard, C2 PA, which forms the current baseline for image authenticity and provenance in practice. The Coalition for Content Provenance and Authenticity (C2 PA) provides a framework for digitally signing photographs, embedding critical metadata, such as location, timestamp, and exposure settings, directly into the image file. This technology, supported by major camera manufacturers, like Leica, Sony, and Nikon, aims to establish a chain of trust for digital content by ensuring its authenticity and provenance. Additionally, C2 PA extends its functionality to AI-generated images, providing attestations that prevent misattribution and distinguish synthetic content from human-captured media. While this framework represents a significant step forward in combating misinformation, it faces substantial challenges when applied to real-world use cases, particularly in the context of news media.  
A key issue arises when news organizations edit images for publication. Common practices, such as cropping, blurring, resizing, or adjusting brightness, often break the original C2 PA signature, rendering the image's authenticity unverifiable. To address this, C2 PA currently requires the use of approved editing applications to re-sign images after modifications. While this approach ensures that edited images retain a valid signature, it introduces a new layer of complexity and trust dependency. News organizations must rely on the integrity of these third-party editing tools, which shifts the trust model away from the original source and toward the software used for editing. This reliance on external applications undermines the end-to-end security that C2 PA aims to achieve, creating a potential vulnerability in the chain of trust.  
A more robust solution would involve a system capable of verifying edits without requiring trust in external editors. For instance, cryptographic techniques could be employed to track and validate modifications, while preserving the original signature. Such a system would allow for transparency in the editing process without compromising the integrity of the content. However, this approach presents its own set of challenges. Implementing a verification mechanism that accommodates common editing practices without breaking the end-to-end security model is a complex task. Furthermore, any changes to the trust model must carefully balance transparency, security, and usability to ensure widespread adoption and effectiveness.  
The limitations of C2 PA in dynamic environments like news media highlight the need for innovative solutions that address the tension between preserving authenticity and accommodating practical editing needs. While the framework provides a strong foundation for digital content provenance, its reliance on approved editing tools introduces trust issues that conflict with its goal of end-to-end security. Developing a system that verifies edits without compromising the trust model remains a critical challenge for the future of digital content authenticity. The process is illustrated on Figure 1.