Technical Guide

C2PA Verification

Master content provenance verification using C2PA standards, digital signatures, and authenticity validation techniques.

🔐 18 min read🏛️ Enterprise Level📜 Standards Focus

1C2PA Standard Overview

The Coalition for Content Provenance and Authenticity (C2PA) standard provides cryptographic proof of content origin and history.

Core Components:

Manifest

Contains claims about content creation, editing, and provenance history.

Assertions

Specific claims about actions performed on the content.

Signatures

Cryptographic signatures that validate the authenticity of claims.

Ingredients

References to source materials used in content creation.

🔗 Key Concept: C2PA creates an immutable chain of custody for digital content.

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2Provenance Chain Analysis

Understanding and validating the complete history of content modifications and transformations.

Chain Validation Steps

1

Origin Verification

Validate the initial content creation claim and creator identity.

2

Modification History

Track all documented edits, transformations, and processing steps.

3

Chain Integrity

Ensure no breaks or tampering in the provenance chain.

3Digital Signature Verification

Cryptographic validation ensures the integrity and authenticity of C2PA manifests.

Signature Types

  • ECDSA: Elliptic Curve signatures
  • RSA: Traditional RSA signatures
  • EdDSA: Edwards curve signatures
  • COSE: CBOR Object Signing

Validation Process

  • • Extract signature from manifest
  • • Verify certificate chain
  • • Check signature validity
  • • Validate timestamp accuracy

Common Signature Issues

Expired Certificates

Certificate validity period has passed

Revoked Certificates

Certificate has been revoked by CA

Invalid Signatures

Signature doesn't match content

4Manifest Inspection

Deep analysis of C2PA manifest structure and content to understand provenance claims.

Manifest Structure

manifest: {
claim_generator: "Adobe Photoshop 24.0"
format: "image/jpeg"
instance_id: "xmp:iid:..."
assertions: [...]
signature: "..."
}

Critical Fields

  • claim_generator: Software used
  • format: Content MIME type
  • instance_id: Unique identifier
  • thumbnail: Content preview

Assertion Types

  • c2pa.actions: Edit history
  • c2pa.hash.data: Content hash
  • stds.exif: Camera metadata
  • c2pa.training-mining: AI usage
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5Trust & Certificate Validation

Establishing trust through certificate authority validation and issuer verification.

Trust Levels

High Trust

Valid certificate from recognized CA, known issuer

Medium Trust

Valid certificate but unknown or unverified issuer

Low Trust

Invalid, expired, or self-signed certificate

Trusted Issuers

Adobe Inc.

Creative Suite

Canon Inc.

Camera Systems

Leica Camera

Professional Cameras

6Implementation Tools

Development SDKs

  • c2pa-node: Node.js SDK
  • c2pa-python: Python SDK
  • c2pa-rs: Rust SDK
  • c2pa-js: Browser SDK

Validation Tools

  • c2pa-tool: CLI validator
  • Verify: Web validator
  • CAI Inspect: Browser extension
  • Adobe Verify: Online tool

Code Example: Basic Verification

import { createC2pa } from 'c2pa-node';
const c2pa = createC2pa();
const result = await c2pa.read('image.jpg');
console.log(result.manifestStore);
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