Show HN: Witness – Capture signed photos/videos with embedded proof-of-origin

I’ve been working on a tool to address one of the biggest problems I see with digital content: the inability to prove that it was captured by a real human, on a real device, at a specific time — without manipulation or AI involvement.

Witness by Reel Human is a privacy-first camera app that generates cryptographically signed photos and videos. Each file includes an embedded JSON manifest with: - The exact capture time - Device info (not user identity) - The app version and signature metadata

The manifest is stored inside the media file (MP4/JPEG) and travels with it, even if shared. The result is a verifiable, human-authored piece of content.

What’s working now (POC): - Android and iOS apps (available for testing) - Signed JSON manifests inside every photo/video - No accounts, no tracking, no upload

What’s coming: - Public verification portal (in progress) - Registry backend with optional verification logging - Open API for platforms to verify content at scale

I’d love your feedback on: - The idea and approach - Security model (crypto choices, manifest design, etc.) - Use cases beyond journalism (legal, education, social media)

Site: https://reel-human.com POC App: https://testflight.apple.com/join/GzfTsCNF Android: https://play.google.com/store/apps/details?id=com.reelhuman.... iOS:

Ask me anything — I’m solo-building this because I think trusted content should be a human right.