Glossary

info

This glossary defines key terms used throughout the documentation and expands on the Glossary in the C2PA Content Credentials specification. In case of a discrepancy, the C2PA specification takes precedence.

Action: An operation that an actor performs on an asset. For example, "create," "embed," or "change contrast" for an image. See Assertions and actions.

Active manifest: The last in the list of manifests inside of a manifest store. The active manifest has the set of content bindings that can be validated. See Working with manifests.

Actor: A person, organization, device, or software product. For example, a camera, image editing software, cloud service, or the person using such tools.

Archive: The serialized, portable representation of a working store saved to a file or stream (typically a .c2pa file). An archive uses the standard JUMBF application/c2pa format and can be read back to restore a Builder. While "working store" emphasizes the editable state, "archive" emphasizes the saved bytes.

Assertion: A data structure in the manifest that contains information about an asset's creation, authorship, how it's been edited, and other relevant information. For a list of standard assertions, see the C2PA technical specification. See also Assertions and actions.

Asset: A file or stream of data containing digital content. Currently, this means certain specific types of image, video, or audio files, but the types of supported assets will expand in the future. See also composed asset and derived asset.

Asset metadata: The portion of an asset that represents non-technical information about the asset and its digital content, as may be stored via standards such as Exif or XMP.

Asset rendition: A representation of an asset (either as a part of an asset or a completely new asset) where the digital content has had a non-editorial transformation action (for example, re-encoding or scaling) applied but where the asset metadata has not been modified.

Authenticity: A property of digital content comprising a set of facts (provenance data and hard bindings) that can be cryptographically verified as not having been tampered with.

Builder: A class in the SDK that you use to create and add a signed manifest to an asset. See Writing manifest data and Builder reference.

Builder intent: See intent.

C2PA: See Coalition for Content Provenance and Authenticity.

C2PA Tool: Command-line utility for working with C2PA manifest data, implemented in the c2pa-rs repository. The name of the utility is "C2PA Tool," while the command to run the utility is c2patool. See C2PA Tool documentation.

C2PA trust list: A C2PA-managed list of X.509 certificate trust anchors that issue certificates to hardware and software signers that use them to sign claims. See Trust lists.

C2PA TSA trust list: A C2PA-managed list of X.509 certificate trust anchors that issue certificates to time-stamp authorities (TSAs). See Trust lists.

CAI: See Content Authenticity Initiative.

CAI open-source SDK: Open-source software for developing Content Credentials applications; includes the C2PA Tool, Rust library, and libraries for Python, C/C++, web JavaScript, Node.js, Android, and iOS. See Introduction.

CAWG: A working group within the Decentralized Identity Foundation (DIF) that defines technical standards for identity assertions (proving who created content), metadata assertions (providing detailed information about content), and training and data mining assertions (specifying how the content may be used).

CBOR: See Concise Binary Object Representation.

Certificate: An electronic document (also called a public key certificate or digital certificate) that vouches for the holder's identity. Like a passport, the certificate is issued by a trusted third party (the certificate authority or CA), cannot be forged, and contains identifying information. See Signing and certificates.

Certificate authority (CA): A trusted third party that verifies the identity of an organization applying for a digital certificate. After verifying the organization's identity, the CA issues a certificate and binds the organization's identity to a public key. A digital certificate can be trusted because it is chained to the CA's root certificate. See Getting a certificate.

Claim: Digitally signed and tamper-evident data in a manifest that references a set of assertions by one or more actors, concerning an asset, and the information necessary to represent the content binding. For example, a claim could specify that a particular image was edited by John Doe using Product X on 05/08/2021 at 11am to change the image contrast.

Claim generator: The non-human (hardware or software) actor that generates the claim about an asset as well as the claim signature, thus leading to the asset's associated manifest.

Claim signature: Part of the manifest that is the digital signature on the claim using an actor's private key. See Signing and certificates.

Coalition for Content Provenance and Authenticity (C2PA): A formal coalition that drafts technical standards and specifications as a foundation for universal content provenance. The C2PA is a mutually governed standards development organization (SDO) under the structure of the Linux Foundation's Joint Development Foundation. For more information, see c2pa.org.

Composed asset: An asset created from multiple parts or fragments of digital content (referred to as ingredients). For example, an image (image A) with another image (image B) imported and superimposed on top of it. In this example, image B is referred to as an ingredient. When starting from an existing asset, it's a special case of a derived asset; however, a composed asset can also be created from a "blank slate."

Concise Binary Object Representation (CBOR): A binary data serialization format loosely based on JSON that allows the transmission of data objects containing name-value pairs, but in a more concise manner than with JSON. CBOR is defined in Internet Standard RFC 8949.

Content Authenticity Initiative (CAI): A group of creators, technologists, journalists, and activists leading the global effort to address digital misinformation and content authenticity. Collaborators include: Adobe, BBC, Microsoft, The New York Times Co., Leica, Nikon, Truepic, and Qualcomm. For more information, see Content Authenticity Initiative.

Content binding: Information that associates specific digital content to a specific manifest associated with a specific asset, either as a hard binding or a soft binding. See Working with manifests.

Content Credentials: Tamper-evident metadata associated with an asset that shows the attribution and provenance details for an asset. Corresponds to a manifest store. See Working with manifests.

Context: A class in the SDK that comprises Settings and optionally a Signer, and that you pass to Reader or Builder to control their behavior. See Settings reference.

ContextProvider: An abstract base class in the SDK that defines the interface Reader and Builder use to access a context.

Cryptographic hash: An algorithm that can be run on digital data such as an image file to produce a unique "fingerprint" value. If the data changes then the hash value will also change.

Derived asset: An asset created by starting from an existing asset and performing actions on it that modify its digital content and asset metadata.

Digital content: The portion of an asset that represents the actual content, such as the pixels of an image, along with any additional technical metadata required to understand the content (for example, a color profile or encoding parameters).

Durable Content Credentials: An approach to help content provenance persist across content platforms by using C2PA manifest data in conjunction with invisible watermarks, actively inserted into the content, and content fingerprints, passively computed from the content. See Durable Content Credentials.

Exchangeable image file format (Exif): A standard that specifies formats for images, sound, and ancillary tags used by digital cameras (including smartphones) and related devices.

Extensible Metadata Platform (XMP): An ISO standard, originally created by Adobe Inc., for the creation, processing, and interchange of standardized and custom metadata for digital documents and data sets. For more information, see Adobe XMP.

Fingerprint: A set of inherent properties computable from digital content that identifies the content or near duplicates of it. See Watermarking and fingerprinting.

Hard binding: One or more cryptographic hashes that uniquely identifies an entire asset or a portion thereof.

Identity assertion: A CAWG assertion that enables a credential holder to prove control over a digital identity and to use that identity to document the named actor's role(s) in an asset's lifecycle. See CAWG - Identity Assertion and Reading CAWG identity assertions.

Identity claims aggregator: An actor that collects CAWG identity claims (attestations) regarding a named actor from various identity providers and can replay those identity claims into identity assertions on behalf of the named actor. This may be the same as the identity assertion generator.

Ingredient: Part of a composed asset, such as an image superimposed on top of another image. See Reading ingredients and Writing ingredients.

Intent: A declaration that tells a Builder what kind of manifest to create. Intents enable validation, add actions required by the C2PA specification, and help prevent invalid operations. There are three intent types: Create for new digital creations (requires a DigitalSourceType and must not have a parent ingredient), Edit for modifying a pre-existing parent asset (must have a parent ingredient), and Update for non-editorial changes such as re-encoding (a restricted version of Edit).

Interim trust list: Initial Content Authenticity trust list that was frozen as of 1 Jan 2026. See Trust lists.

Invisible watermark: See watermark.

JSON (JavaScript Object Notation): A lightweight data-interchange and file format that uses human-readable text to store and transmit data objects consisting of attribute-value pairs and arrays (or other serializable values). For more information, see json.org.

JPEG universal metadata box format (JUMBF): A proposed International Organization for Standardization (ISO) standard that provides a mechanism to embed and refer to generic metadata in JPEG files.

Manifest: The set of information about the provenance of an asset based on the combination of one or more assertions (including content bindings), a single claim, and a claim signature. A manifest is part of a manifest store. See Working with manifests.

Manifest archive: See archive.

Manifest consumer: An actor who consumes an asset with an associated manifest for the purpose of obtaining the provenance data from the manifest.

Manifest repository: A repository that contains manifests and manifest stores, and which can be searched using a content binding.

Manifest store: A collection of manifests that can either be embedded into an asset or be external to it. See Working with manifests.

Manifest working store: See working store.

Metadata: See asset metadata.

Metadata assertion: A CAWG assertion for binding metadata from standards such as XMP, IPTC, and Exif to a C2PA manifest in a tamper-evident way. Unlike the c2pa.metadata assertion from the C2PA technical specification, this specification places no restrictions on which metadata fields may be included, so it supports a broader set of use cases. This makes it well-suited for use in gathered assertions in the C2PA claim schema, where the signer of the C2PA manifest does not attest to the accuracy of the provided metadata but still ensures the integrity of the C2PA manifest. See CAWG - Metadata Assertion.

Online Certificate Status Protocol (OCSP): An internet protocol used for obtaining the revocation status of an X.509 digital certificate, that is, whether the certificate is still valid. See IETF RFC 6960.

Private key: In public key cryptography, a unique digital key (very long number) used to decode messages that were encrypted with the corresponding public key. Every private key matches to exactly one public key and is the only key that can decode messages encoded by the matching public key. To ensure security, a private key's owner must never disclose it to anyone else.

Provenance: The logical concept of understanding the history of an asset and its interaction with actors and other assets, as represented by the provenance data.

Provenance data: The set of manifests for an asset and, in the case of a composed asset, its ingredients.

Public key: In public key cryptography, a unique digital key (very long number) used to encode messages that can then be decrypted with the corresponding private key. Every public key matches to exactly one private key. A message encoded using a particular public key can be decoded only by using the matching private key. Public keys can be freely disseminated without compromising security.

Reader: A class in the SDK that you use to read and validate a manifest store from an asset. See Reading manifest data and Reader reference.

Redaction: Removing an assertion from an asset's manifest when the asset is used as an ingredient. See the C2PA technical specification.

Resource: Binary assets referenced by manifest assertions, such as thumbnails or ingredient thumbnails.

Settings: A class in the SDK that controls behavior such as thumbnail generation, trust lists, and verification flags. See Settings reference.

Sidecar file: A file containing a manifest store, with the same base name as the asset file but with a .c2pa extension. A sidecar file is an alternative to embedding the manifest store in an asset's metadata. For example, an asset named cat.jpg would have a sidecar file named cat.c2pa. See Working with manifests.

Signer: An actor whose credential's private key is used to sign a claim. The signer is identified by the subject of the credential. See Signing and certificates.

Soft binding: A content identifier that is either embedded as a watermark in the digital content or is not statistically unique. For example, TrustMark watermarks are added via soft bindings. See Watermarking and fingerprinting.

Time-stamp: A time-stamp issued by a trusted time-stamp authority used to prove that a manifest signature existed at a certain date and time. See Trust lists.

Time-stamp authority: A trusted third party that provides an RFC 3161-compliant time-stamp authority (TSA). See RFC 3161, section 1.

Training and data mining assertion: A CAWG assertion that enables someone to provide information about whether an asset with C2PA metadata may be used for data mining or AI/ML training. See CAWG - Training and Data Mining Assertion.

Trust list: See C2PA trust list.

Trust signals: The collection of information that can inform an actor's judgment of the trustworthiness of an asset. These are in addition to the signer of a claim, upon which the fundamental trust model relies.

TrustMark: An open-source universal watermarking system for images that several Adobe products use to make Durable Content Credentials. See TrustMark watermarking.

TSA: See time-stamp authority.

Validation: The process of determining if Content Credentials are properly configured and signed. For example: Is an asset actually the one described by its associated manifest, and does the manifest follow the format and rules defined in the C2PA specification. See Manifest validation.

Validator: A manifest consumer who performs validation on an active manifest. See Manifest validation.

Verifiable credential (VC): A tamper-evident credential whose authorship can be cryptographically verified. This term may be used in the generic sense or may refer to the W3C Recommendation Verifiable Credentials Data Model.

W3C decentralized identifier: A portable URL-based identifier, also known as a DID, associated with an entity. These identifiers are most often used in a W3C verifiable credential and are associated with credential subjects such that a W3C verifiable credential itself can be easily ported from one repository to another without the need to reissue the credential. An example of a DID is did:example:123456abcdef.

W3C decentralized identifier document: Also referred to as a DID document, this is a document that is accessible using a verifiable data registry and contains information related to a specific W3C decentralized identifier, such as the associated repository and public key information.

W3C verifiable credential: A tamper-evident credential that has authorship that can be cryptographically verified.

Watermark: Information incorporated (perceptibly or imperceptibly) into the digital content of an asset which can be used, for example, to uniquely identify the asset or to store a reference to a manifest. See Watermarking and fingerprinting.

Working store: An editable, in-progress manifest represented by a Builder that has not yet been signed and bound to an asset. A working store contains the C2PA manifest state (claims, ingredients, assertions) being assembled. It can be serialized to an archive for saving, transferring, or resuming later, and uses the same standard JUMBF application/c2pa format as signed manifests.

XMP: See Extensible Metadata Platform.