Back to Blog

VerifiablyBased Journal

What Makes a Photo Verifiable?

A practical walkthrough of how device-attested, C2PA-signed captures turn images into portable proofs.

Most integrity systems still depend on trust in platforms. We are building for proof portability: the evidence should travel with the image.

The Three Guarantees

  • Integrity from the moment of capture, signed in the device's secure hardware
  • Cryptographic binding between the image and its provenance claim
  • Public verifiability without access to private infrastructure

Why This Matters

If authenticity depends on a closed system, an external reviewer still has to trust someone. A verifiable artifact should be auditable anywhere.

PropertyLegacy Upload ProofC2PA-Signed Capture
Verify offlineNoYes
Detect tamperingOften indirectDirect
Portable evidenceLimitedNative

Minimal Verification Flow

import { verifyProofBundle } from "@verifiablybased/sdk";
 
const result = await verifyProofBundle(bundle);
 
if (!result.valid) {
  throw new Error("Proof verification failed");
}
 
console.log("Signer:", result.signer);
console.log("SignedAt:", result.signedAt);

The verifier does not need to know who sent the file first. They only need the bundle and the public verification logic.