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C2PA Technical Specification

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Relevant to AI safety governance as a technical standard for AI content disclosure and provenance tracking; useful for those studying infrastructure solutions to synthetic media and disinformation risks.

Metadata

Importance: 62/100standardreference

Summary

The Coalition for Content Provenance and Authenticity (C2PA) Technical Specification defines an open standard for embedding cryptographically signed provenance metadata into digital content, enabling verification of origin, authorship, and modification history. It addresses the growing challenge of synthetic and manipulated media by creating an auditable chain of custody for images, videos, audio, and documents. This specification is foundational infrastructure for distinguishing authentic content from AI-generated or altered media.

Key Points

  • Defines a standardized format for Content Credentials: cryptographically signed assertions about content origin, authorship, and edit history embedded in media files.
  • Uses a 'manifest' structure with a chain of provenance records, allowing verification of every transformation a piece of content has undergone.
  • Supports AI-generated content labeling, enabling disclosure of when and how AI tools were used in content creation or modification.
  • Employs public-key cryptography and X.509 certificates to bind provenance claims to verified identities (publishers, cameras, software).
  • Backed by major industry players (Adobe, Microsoft, Intel, BBC, Sony) as a cross-sector trust infrastructure for media authenticity.

Review

The Coalition for Content Provenance and Authenticity (C2PA) has developed a comprehensive technical specification addressing the growing challenges of digital content trust and misinformation. The specification introduces a robust system for creating cryptographically verifiable manifests that track the entire lifecycle of a digital asset, from creation through subsequent modifications. The core methodology involves creating digitally signed claims and assertions that capture metadata about an asset's origin, transformations, and actors involved. By utilizing techniques like hard and soft content bindings, digital signatures, and verifiable credentials, C2PA enables platforms and users to establish the authenticity and provenance of digital content. The specification is designed to be flexible, privacy-preserving, and implementable across various media types and platforms, with careful consideration of potential abuse vectors and security implications.

Cited by 2 pages

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 C2PA Technical Specification

 
 Table of Contents 
 
 1. Introduction 
 
 1.1. Overview 

 1.2. Scope 

 1.3. Technical Overview 

 1.4. Establishing Trust 

 1.5. An Example 

 1.6. Design Goals 

 

 2. Glossary 
 
 2.1. Introductory terms 

 2.2. Assets and Content 

 2.3. Core Aspects of C2PA 

 2.4. Additional Terms 

 2.5. Overview 

 

 3. Normative References 
 
 3.1. Core Formats 

 3.2. Schemas 

 3.3. Digital & Electronic Signatures 

 3.4. Other 

 

 4. Standard Terms 

 5. Assertions 
 
 5.1. General 

 5.2. Labels 

 5.3. Versioning 

 5.4. Multiple Instances 

 5.5. Assertion Store 

 5.6. Embedded vs Externally-Stored Data 

 5.7. Redaction of Assertions 

 

 6. Unique Identifiers 
 
 6.1. Using XMP 

 6.2. Other Identifiers 

 6.3. URI References 

 

 7. W3C Verifiable Credentials 
 
 7.1. General 

 7.2. VCStore 

 7.3. Using Credentials 

 7.4. Credential Security Considerations 

 

 8. Binding to Content 
 
 8.1. Overview 

 8.2. Hard Bindings 

 8.3. Soft Bindings 

 

 9. Claims 
 
 9.1. Overview 

 9.2. Syntax 

 9.3. Creating a Claim 

 9.4. Multiple Step Processing 

 

 10. Manifests 
 
 10.1. Use of JUMBF 

 10.2. Types of Manifests 

 10.3. Embedding manifests into assets 

 10.4. External Manifests 

 10.5. Embedding a Reference to the Active Manifest 

 

 11. Entity Diagram 

 12. Cryptography 
 
 12.1. Hashing 

 12.2. Digital Signatures 

 

 13. Trust Model 
 
 13.1. Overview 

 13.2. Identity of Signers 

 13.3. Signer Credential Trust 

 13.4. Credential Types 

 13.5. Identity In Assertions 

 13.6. Statements 

 

 14. Validation 
 
 14.1. Locating the Active Manifest 

 14.2. Locating the Claim 

 14.3. Validate the Signature 

 14.4. Validate the Time-Stamp 

 14.5. Validate the Credential Revocation Information 

 14.6. Validate the Assertions 

 14.7. Recursively Validating Integrity of Ingredients 

 14.8. Visual look of Validation 

 14.9. Validate the Asset’s Content 

 

 15. User Experience 
 
 15.1. Approach 

 15.2. Principles 

 15.3. Disclosure Levels 

 15.4. Public Review, Feedback and Evolution 

 

 16. Information security 
 
 16.1. Threats and Security Considerations 

 16.2. Harms, Misuse, and Abuse 

 

 17. C2PA Standard Assertions 
 
 17.1. Introduction 

 17.2. Use of CBOR 

 17.3. Metadata About Assertions 

 17.4. Standard C2PA Assertion Summary 

 17.5. Data Hash 

 17.6. BMFF-Based Hash 

 17.7. Soft Binding 

 17.8. Cloud Data 

 17.9. Thumbnail 

 17.10. Actions 

 17.11. Ingredient 

 17.12. Depthmap 

 17.13. Exif Information 

 17.14. IPTC Photo Metadata 

 17.15. Use of Schema.org 

 17.16. Common Data Mode

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