Trust Nobody: Privacy-Preserving Proofs for Edited Photos with Your Laptop

Pierpaolo Della Monica, Ivan Visconti, Andrea Vitaletti and Marco Zecchini

Sapienza University of Rome, Italy

Welcome to the official GitHub repository for our IEEE S&P25 paper "Trust Nobody: Privacy-Preserving Proofs for Edited Photos with Your Laptop". This repository contains the implementation of the experiments discussed in the paper, providing all the necessary resources to reproduce our results and explore the techniques we developed.

[Abstract]

In this work, we introduce a novel system for proving and verifying the authenticity of transformations applied to confidential images. The proposed system ensures:

1. Confidentiality – the original image remains private,
2. Efficient Proof Generation – the proof certifying the correctness of the transformation can be computed efficiently on a common laptop, even for high-resolution images,
3. Authenticity – only the advertised transformations have been applied,
4. Fast Fraud Detection – enabling rapid identification of fraudulent proofs.

Our contributions include new definitions that model confidentiality and adaptive adversaries, techniques to accelerate the prover, and an efficient construction based on custom signatures and hashes. We also propose a less efficient construction utilizing signatures and hashes from the C2PA specifications. Experimental results confirm the practicality of our approach, allowing the computation of authentic transformations of high-resolution images on standard computing resources. Prior work either demands expensive computing power or fails to meet confidentiality requirements.