Generative AI content

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t01_primary_claims.json --source-file <local-raw-pdf>

Example C2PA Manifest of a Photograph A Manifest Consumer, such as a C2PA Validator, could help users to establish the trustworthiness of the asset by first validating the digital signature and its associated credential.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t01_primary_claims.json --source-file <local-raw-pdf>

C2PA Manifest Store A collection of C2PA Manifests that can either be embedded into an asset or be external to its asset.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t01_primary_claims.json --source-file <local-raw-pdf>

If a C2PA Manifest is a Content Credential, then multiple C2PA Manifest or the broader, universal concept is Content Credentials.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t01_primary_claims.json --source-file <local-raw-pdf>

C2PA Trust List A C2PA-managed list of X.509 certificate trust anchors that issue certificates to hardware & software signers that are trusted to sign claims.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t01_primary_claims.json --source-file <local-raw-pdf>

Manifest Repository A repository into which C2PA Manifests and C2PA Manifest Stores can be placed, and which can be searched using a content binding.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t01_primary_claims.json --source-file <local-raw-pdf>

The label would then consist of an incremented version number, for example moving from c2pa.hash.bmff (deprecated) to c2pa.hash.bmff.v2.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t01_primary_claims.json --source-file <local-raw-pdf>

For example, if a manifest contains a single assertion of type c2pa.metadata, then the assertion label will be c2pa.metadata.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t01_primary_claims.json --source-file <local-raw-pdf>

Unlike embedded assertion data, cloud data is not retrieved nor validated as part of manifest validation, and are only retrieved and validated when specifically needed by an application according to a different set of validation rules as described in Section 15.7, “Validate the Assertions”.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t01_primary_claims.json --source-file <local-raw-pdf>

It is also strongly recommended that the claim generator should add a c2pa.redaction action assertion with a redacted field as described in Section 18.12.2, “Parameters”.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t01_primary_claims.json --source-file <local-raw-pdf>

Using XMP values When an asset contains embedded XMP which include values for xmpMM:DocumentID and/or xmpMM:InstanceID as defined in XMP Specification Part 2, 2.2, those values shall be included in a metadata assertion and should be used as identifiers for the asset.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t02_primary_claims.json --source-file <local-raw-pdf>

URI References All references to information in the manifest, whether stored internally to the asset (i.e., embedded) or stored externally to the asset (e.g., in the cloud), shall be referenced via JUMBF URI references as defined in ISO 19566-5, C.2.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t02_primary_claims.json --source-file <local-raw-pdf>

We use a socket/plug here to allow hashed-uri-map to be used in individual files without having the map defined in the same file $hashed-uri-map /= { "url": url-regexp-type, ; JUMBF URI reference ? "alg": tstr .size (1..max-tstr-length), ; A string identifying the cryptographic hash algorithm used to compute all hashes in this claim, taken from the C2PA hash algorithm identifier list.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t02_primary_claims.json --source-file <local-raw-pdf>

These self#jumbf URIs may be relative to the entire C2PA Manifest Store, in which case they shall start with a / (U+002F, Slash), or relative to the current C2PA Manifest.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t02_primary_claims.json --source-file <local-raw-pdf>

z]{2,6}\\b[-a-zA-Z0-9@:%_\\+.~#?&//=]*" In keeping with common practice, it is recommended that the https scheme be used to retrieve assertion data to protect the privacy of the data in transit, but http is also permitted because the NOTE data’s integrity is protected by the hash field and this privacy may not be required in all circumstances.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t02_primary_claims.json --source-file <local-raw-pdf>

As described in the latest version of JUMBF (ISO 19566-5:2023), a new Private field can be present as part of any JUMBF Description box.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t02_primary_claims.json --source-file <local-raw-pdf>

Hashing using byte ranges The simplest type of hard binding that can be used to detect tampering is a cryptographic hashing algorithm, as described in Section 11.3.4.2, “Hashing”, over some or all of the bytes of an asset.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t02_primary_claims.json --source-file <local-raw-pdf>

(fMP4) files, the assertion itself must be combined with chunk-specific hashing information which is located as specified in Section 11.3.3, “Embedding manifests into BMFF-based assets”.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t02_primary_claims.json --source-file <local-raw-pdf>

Asset Metadata Bindings Signers of the C2PA Manifest are not required to sign the asset metadata not contained within the C2PA Manifest.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t02_primary_claims.json --source-file <local-raw-pdf>

Any asset metadata values that are supported by the common metadata assertion, as described in Appendix A, Implementation Details for c2pa.metadata, and can be asserted by the signer should be copied into such an assertion and included in the C2PA Manifest.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t02_primary_claims.json --source-file <local-raw-pdf>

A claim has all the same properties as an assertion including being assigned the label (c2pa.claim.v2) and supporting the use of assertion metadata.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t03_primary_claims.json --source-file <local-raw-pdf>

It may also contain a version field and/or an icon field, though any other field is permitted, using the standard entity-specific labels' format described in Section 6.2, “Labels”.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t03_primary_claims.json --source-file <local-raw-pdf>

The serialized COSE_Sign1_Tagged structure resulting from the digital signature procedure is written into the C2PA Claim Signature box.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t03_primary_claims.json --source-file <local-raw-pdf>

Time-stamps If possible, the signer should use a RFC3161-compliant Time Stamp Authority (TSA) (RFC 3161 section 1) to obtain a trusted time-stamp proving that the signature itself actually existed at a certain date and time and incorporate that into the COSE_Sign1_Tagged structure as a countersignature.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t03_primary_claims.json --source-file <local-raw-pdf>

The above definition is a CBOR adaptation of a subset of the schema from JAdES section 5.3.4 and its NOTE JSON schema, except with the modification that the content of val is a byte string containing the content of the TimeStampResp, and not a Base64-encoded version of the same.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t03_primary_claims.json --source-file <local-raw-pdf>

If credential revocation information is attached in this manner, a trusted time-stamp must also be obtained after signing, as described in Section 10.3.2.5, “Time-stamps”.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t03_primary_claims.json --source-file <local-raw-pdf>

For example, in JPEG-1 files, the entire C2PA Manifest Store must appear in the file before the image data, and so its size will affect the file offsets of content being authenticated.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t03_primary_claims.json --source-file <local-raw-pdf>

If a manifest is embedded in the center of a JPEG-1 file in an APP11 segment, then the claim creator may exclude the APP11 segment(s) from the hash calculation.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t03_primary_claims.json --source-file <local-raw-pdf>

In the case of JPEG-1 files, this can be achieved either by eliminating padding or by ensuring that the JFIF APP11/C2PA segments cannot be shortened of changed to a different segment type.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t03_primary_claims.json --source-file <local-raw-pdf>

Complete the C2PA Manifest At this point all of the boxes that comprise the entire C2PA Manifest for the asset are completed and can be (if not already) constructed into its final form.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t03_primary_claims.json --source-file <local-raw-pdf>

The asset’s C2PA Manifest, along with the manifests of any ingredients, are combined together to form the complete C2PA Manifest Store.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t04_primary_claims.json --source-file <local-raw-pdf>

Processing Rules A C2PA Manifest Consumer shall never process an assertion, assertion store, claim, claim signature or C2PA Manifest that is not contained inside of a C2PA Manifest Store.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t04_primary_claims.json --source-file <local-raw-pdf>

Based on a similar box in JPEG-XL (ISO 18181-2), the brob box is a content box whose contents are the Brotli-compressed bytes of either a standard manifest or update manifest, as described in the compressed manifests clause.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t04_primary_claims.json --source-file <local-raw-pdf>

Example of a compressed manifest Hashing a compressed box is done in the same way as any other box, as described in Section 8.3.1.3, “Hashing JUMBF Boxes”.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t04_primary_claims.json --source-file <local-raw-pdf>

This implies that given a hashed_uri reference from an ingredient assertion to a C2PA Manifest via the c2pa_manifest field, the hash is calculated using the same process as any other JUMBF NOTE superbox: over the JUMBF Description Box and the brob box with its compressed payload, but excluding the superbox’s header.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t04_primary_claims.json --source-file <local-raw-pdf>

Labels As described in the JUMBF specification (ISO 19566-5, A.3), a label shall be stored as ISO/IEC 10646 characters in the UTF-8 encoding.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t04_primary_claims.json --source-file <local-raw-pdf>

C2PA Manifest Store The C2PA Manifest Store is a JUMBF superbox composed of a series of other JUMBF boxes and superboxes, each identified by their own UUID and label in their JUMBF Description box.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t04_primary_claims.json --source-file <local-raw-pdf>

The C2PA Manifest Store shall have a label of c2pa, a UUID of 0x63327061-0011-0010-8000-00AA00389B71 (c2pa) and shall contain one or more C2PA manifest superboxes, also known as C2PA Manifests.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t04_primary_claims.json --source-file <local-raw-pdf>

It shall contain one or more JUMBF superboxes (called C2PA Assertion boxes) whose JUMBF type defines the BMFF type of the sub-boxes that contain the assertion data (see ISO 19566-5, Annex B, Table B.1 and ISO 19566-5/AMD-1, Annex B).

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t04_primary_claims.json --source-file <local-raw-pdf>

The JUMBF Content Type (ISO 19566-5, Annex B) box(es) contained in each assertion superbox should be CBOR Content Type (cbor), JSON Content Type (json), Embedded File Content Type (bfdb & bidb) or UUID Content Type (uuid) though any Content Type defined in JUMBF and its amendments is permitted.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t04_primary_claims.json --source-file <local-raw-pdf>

Standard Manifests A standard C2PA Manifest (UUID: 0x63326D61-0011-0010-8000-00AA00389B71 (c2ma)) shall contain exactly one hard binding to content assertion - either a c2pa.hash.data, c2pa.hash.boxes, c2pa.hash.collection.data, or c2pa.hash.bmff.v2 based on the type of asset and version for which the manifest is destined.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t05_primary_claims.json --source-file <local-raw-pdf>

An Update Manifest shall not contain assertions of types c2pa.hash.data, c2pa.hash.boxes, c2pa.hash.collection.data, or c2pa.hash.bmff.v2 because the content has not changed and therefore the bindings need not be updated.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t05_primary_claims.json --source-file <local-raw-pdf>

In the case of a file offset hash (c2pa.hash.data), the C2PA Manifest Store has to continue to start at the same file offset after updating - only its length can change.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t05_primary_claims.json --source-file <local-raw-pdf>

NOTE C2PA is asking for feedback from the audio community if embedding the C2PA Manifest Store in an ID3v2 container will work with FLAC or if we will need to use the native FLAC container.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t05_primary_claims.json --source-file <local-raw-pdf>

Since a single marker segment in JPEG 1 cannot be larger than 64K bytes, it is likely that multiple APP11 segments will be required, and they shall be constructed as per the JPEG 1 standard and ISO 19566-5, D.2.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t05_primary_claims.json --source-file <local-raw-pdf>

Embedding manifests into PNG The C2PA Manifest Store shall be embedded using an ancillary, private, not safe to copy, chunk type of 'caBX' (as per PNG, 4.7.2).

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t05_primary_claims.json --source-file <local-raw-pdf>

The GEOB’s MIME type field shall be present and shall use the value for the media type for JUMBF as described in Section 11.4, “External Manifests”.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t05_primary_claims.json --source-file <local-raw-pdf>

The C2PA Manifest Store shall be embedded into a TIFF-compatible file (i.e., TIFF/EP, DNG or other TIFF-based RAW formats) as the data of a tag with ID 52545 (decimal) or 0xCD41 (hexadecimal), with a tag type of 7.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t05_primary_claims.json --source-file <local-raw-pdf>

The C2PA table format is not yet defined in the Open Font Format nor OpenType specification; the following definition is preliminary: 11.3.1.8.1.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t05_primary_claims.json --source-file <local-raw-pdf>

If a URI is not provided a NULL offset = 0x0000 should be used. uint16 activeManifestUriLength Length of URI in bytes. uint16 reserved Reserved for future use.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t05_primary_claims.json --source-file <local-raw-pdf>

A C2PA Manifest Consumer shall process all C2PA Manifests in all C2PA Manifest Stores as if they were contained in a single C2PA Manifest Store.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t06_primary_claims.json --source-file <local-raw-pdf>

Because a JUMBF URI is always a full URI, meaning that it starts at a given C2PA Manifest, and all NOTE C2PA Manifests are considered to be contained in a single C2PA Manifest Store, using such a URI to refer to a parentOf ingredient across C2PA Manifest Stores in a PDF is acceptable.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t06_primary_claims.json --source-file <local-raw-pdf>

It can also be used to provide provenance for specific pieces of content by adding the AF entry to the object (via property list) or a structure element, as described in the Associated Files clause of ISO 32000-2 (14.13.1).

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t06_primary_claims.json --source-file <local-raw-pdf>

Embedded Files Document Catalog Dictionary Active Manifest Page 1 Assertions Claim Content Stream Claim Signature Ingredient Manifest (Image) Resources Assertions Image XObject Claim Claim Signature Font Ingredient Manifest (Font) Assertions Claim Claim Signature Text is not SVG - cannot display Figure 13.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t06_primary_claims.json --source-file <local-raw-pdf>

The 'uuid' Box for C2PA All BMFF-based C2PA assets, whether they are timed (e.g., videos with or without audio tracks), untimed (e.g., still photos) or mixed (e.g., live or animated photos) audiovisual media, shall use a 'uuid' box that adheres to the following syntax and semantics defined below.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t06_primary_claims.json --source-file <local-raw-pdf>

Regarding unique ids: There are cases, such as fragmented MP4 (fMP4), where the id for a subset of the asset, such as the track_id field of the 'tkhd' box, is only locally unique to a subset of the overall asset rather than globally unique to the asset.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t06_primary_claims.json --source-file <local-raw-pdf>

data When box_purpose is manifest, the first 8 bytes inside 'data' shall be the absolute file byte offset to the first auxiliary 'uuid' C2PA box with box_purpose equal to merkle.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t06_primary_claims.json --source-file <local-raw-pdf>

For fragmented MP4 (fMP4) files, an identical 'uuid' C2PA box of type manifest shall be present in each initialization segment; the C2PA Manifest Store shall be identical.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t06_primary_claims.json --source-file <local-raw-pdf>

For timed-media where an 'stco' or 'co64' box is present, the hash used for a given leaf node in the Merkle tree shall be computed over an individual subset of samples as defined by that box.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t06_primary_claims.json --source-file <local-raw-pdf>

Taking a c2pa-compliant fMP4 asset which is split across multiple files (i.e., has 'c2pa' boxes of types 'manifest' and 'merkle') and appending the individual files together will not produce a single file which is 'c2pa' compliant (nor vice-versa).

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t06_primary_claims.json --source-file <local-raw-pdf>

If there are multiple auxiliary 'uuid' C2PA boxes with box_purpose merkle for a given Merkle tree in a single file, each shall be followed by sufficient padding bytes (zero or more) to make all auxiliary 'uuid' C2PA boxes for that Merkle tree a fixed size.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t07_primary_claims.json --source-file <local-raw-pdf>

As a result, such a server must either hash said streams and create a C2PA Manifest each time the content is consumed or, if generation is deterministic, create and cache the hashes and C2PA Manifests once and then embed them at consumption time.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t07_primary_claims.json --source-file <local-raw-pdf>

Exclusion List Requirements For all c2pa.hash.bmff.v2 assertions, the following entries shall always appear on the exclusion list.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t07_primary_claims.json --source-file <local-raw-pdf>

Size requirements If a BMFF-based asset uses 32-bit sizes or offsets in any box(es), e.g. the 'stco' box, and adding boxes to conform to this specification will push the file size over 4 gigabytes, it is the responsibility of the manifest creator to edit the file to use appropriate sizes and offsets, e.g. by replacing the 'stco' box with a 'co64' box, before creating the manifest.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t07_primary_claims.json --source-file <local-raw-pdf>

Hashing the ZIP Central Directory As described in 4.3.12 of the ZIP AppNote, the Central Directory is an array of central directory headers - one per file in the ZIP archive.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t07_primary_claims.json --source-file <local-raw-pdf>

It is immediately followed by the End of Central Directory record (ZIP AppNote, 4.3.16), which contains information about the ZIP archive itself.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t07_primary_claims.json --source-file <local-raw-pdf>

Placement of the Manifest Store The C2PA Manifest Store shall be stored in the META-INF directory of the ZIP archive with a filename of content_credential.c2pa and a media type as recommended for external manifests.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t07_primary_claims.json --source-file <local-raw-pdf>

These lists establish the allowed algorithms and key types by referencing an algorithm identifier from the relevant standards that define algorithms for COSE and their mappings to CBOR identifiers, including but not limited to RFC and RFC 8230.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t07_primary_claims.json --source-file <local-raw-pdf>

Nothing in Section 11.3.4.2, “Hashing” shall apply to this use of hash algorithms; if a digital signature algorithm is present in the digital signature algorithm and key type registry, the use of its specified hash algorithm in the signature scheme shall be allowed and followed.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t07_primary_claims.json --source-file <local-raw-pdf>

ECDSA requires elliptic curve keys on the P-256, P-384, or P-521 elliptic curves. ◦ Although it is recommended to use P-256 keys with ES256, P-384 keys with ES384, and P-521 keys with ES512, it is not required.

Evidence card JSONRendered card

Download the PDF to a local file, then run the committed verifier. A changed PDF is reported as drift rather than silently accepted.

python scripts/verify_primary_public_claim_group.py artifacts/cb7k_dom004_t07_primary_claims.json --source-file <local-raw-pdf>

Use of COSE The signature for the CBOR-encoded claim is produced by CBOR Object Signing and Encryption (COSE) as described in RFC 8152 sections 4.2 and 4.4.

Evidence card JSONRendered card