before-after – Cryptographic proof for field service photo verification

Summary: before-after is a mobile app that creates cryptographically signed, GPS-stamped, and RFC 3161-timestamped before/after photo proofs for field workers. It ensures any photo edits invalidate the signature, enabling clients to verify authenticity locally without backend trust. Proofs include Ed25519 signatures, SHA-256 hashes, external timestamps, and meter-level GPS accuracy, exportable as JSON, PDF, or Legal format.

What it does

The app captures photos with cryptographic signatures, GPS data, and external timestamps to prevent tampering. Any modification breaks the proof, which clients verify offline.

Who it's for

Field workers and clients needing tamper-proof photo evidence for job verification and dispute resolution.

Why it matters

It solves the problem of unverifiable photo evidence by providing neutral, cryptographically secured proof without relying on centralized authorities.