C2PA and pHash: Two Technologies for Photographer Attribution

Photographers face a persistent problem: when images go viral on social media, metadata stripping erases credit. The Coalition for Content Provenance and Authenticity (C2PA), backed by Adobe, Microsoft, Google, Amazon, and Meta, embeds author, time, and location data at capture. However, five years after launch, fewer than 1% of news images or videos globally include C2PA info, per the Reuters Institute. Social media platforms intentionally strip metadata during compression, citing storage costs: an estimated 14 billion daily uploads would require 1.4 petabytes of extra storage for C2PA metadata. Perceptual hashing (pHash) offers an alternative: a 64-character digital fingerprint is generated from an image, which can be compared to a library of hashes to identify the original creator without needing attached metadata. The photo can be cropped, compressed, or screenshotted and still be traceable. pHash requires no extra storage from tech companies, aligning incentives better than C2PA. Both technologies can coexist: photographers can enable C2PA on cameras for a digital trail, while pHash-based services (like Provyn, founded by Chris McGreevy) help secure credit across the internet. The ultimate goal is proper attribution, and the path forward remains open.