Talk Abstract: Verifying where and when a digital image was taken has become increasingly difficult; this issue of image provenance is especially concerning in the realm of news media. The Coalition for Content Provenance and Authenticity (C2PA) has developed a standard to verify image provenance that relies on digital signatures produced by cameras. However, photos are usually edited before being published, and a signature on an original photo cannot be verified given only the published edited image. The C2PA proposes that editing applications digitally sign edit records, but this places enormous trust in these applications. In this talk, I will describe VerITAS, a system that uses zero-knowledge proofs (zk-SNARKs) to prove that only certain edits have been applied to a signed photo. Using such proofs means that news consumers need not trust photo editors, thereby solving the trust problem posed by the C2PA standard. While past work has created image editing proofs for photos, VerITAS is the first to do so for realistically large images (30 megapixels).

Speaker Biography: Trisha is a third-year computer science PhD student at Stanford University working with Dan Boneh in the Applied Cryptography Group. Her work focuses on giving mathematical guarantees for information privacy and integrity. She has worked on developing more efficient and novel theoretical techniques for zero-knowledge proofs as well as applying these techniques to real-world application to demonstrate their usefulness.