C2PA formats we sign and check
Encypher puts a C2PAC2PA: The Coalition for Content Provenance and Authenticity: the group that publishes the open standard for content labels. label on 75+ formats for signing and verification: pictures, sound, video, documents, fonts and text. Most formats keep the label where the C2PA standard says. A few use an experimental spot of ours, marked below.
- Sign and check
- 79 formats do both.
- Sign
- 86 formats.
- Check
- 79 formats.
- Standard's test
- 20 media typesMIME type: The standard name for a file format, such as image/jpeg or audio/wav, that software uses to decide how to read a file. passed the C2PA Conformance ProgramC2PA Conformance Program: The C2PA's test that checks a product builds and reads labels the way the standard says before it is listed as conforming. under C2PA 2.2.
Coverage by kind of file
Counts are formats that we can both sign and check.
| Kind | Formats | Where the label goes | Format guides |
|---|---|---|---|
| Images | 13 | A JUMBFJUMBF: JPEG Universal Metadata Box Format: the container that holds a C2PA label inside a media file. box in the image's metadataMetadata: Data stored beside the content in a file, such as author, camera or date. Many tools strip it when they copy or upload a file. spot. | JPEG, PNG, WebP, TIFF, AVIF, HEIC, HEIC Sequence, HEIF, HEIF Sequence, SVG, DNG, GIF, JPEG XL |
| Audio | 6 | A chunk or tag the format already has: RIFFRIFF: The chunk-based file layout behind WAV, AVI and WebP., ID3ID3: The tag block in an MP3 file that holds its title, artist and other details. or ISO BMFFBMFF: ISO Base Media File Format: the box structure behind MP4, MOV, HEIF and similar files.. | WAV, MP3, M4A, AAC, FLAC, MPA |
| Video | 7 | A box in an ISO BMFF file such as MP4 or MOV, where C2PA defines it. Matroska and MXF use an experimental Encypher spot, because C2PA does not define one yet. | MP4, MOV, M4V, AVI |
| Documents | 37 | A box Encypher places in the document's own structure. | PDF, EPUB, DOCX, ODT, OXPS |
| Fonts | 3 | A table inside the font file. | OTF, TTF, SFNT |
| Text | 13 | Characters that draw nothing, inside the text itself. | Articles, posts, plain text |
Text has no box, so the label rides inside it
An article or a post is just a run of letters. There is no file box to hold a label.
So the C2PA standard for unstructured textC2PA text-provenance standard: The part of the C2PA standard that puts a signed label inside plain text, using invisible Unicode characters. stores it as hidden characters in the text. Encypher wrote that part of the standard.
The standard's test covers a smaller set
The C2PA tests products one media type at a time. Our record covers 20 media types under C2PA 2.2.
The other formats follow the same standard. They are simply not part of that formal test yet. The two counts measure different things.
For engineers
Show the technical detail
Every format with its own page
| Format | MIME type | Where the manifest goes |
|---|---|---|
| JPEG | image/jpeg | JUMBF manifest store in APP11 marker segments |
| PNG | image/png | JUMBF manifest store in a caBX chunk |
| WebP | image/webp | JUMBF manifest store in a C2PA chunk of the RIFF container |
| TIFF | image/tiff | JUMBF manifest store in a dedicated tag of the TIFF image file directory (IFD) |
| AVIF | image/avif | JUMBF manifest store in a C2PA uuid box in the ISO BMFF structure |
| HEIC | image/heic | JUMBF manifest store in a C2PA uuid box in the ISO BMFF structure |
| HEIC Sequence | image/heic-sequence | JUMBF manifest store in a C2PA uuid box in the ISO BMFF structure |
| HEIF | image/heif | JUMBF manifest store in a C2PA uuid box in the ISO BMFF structure |
| HEIF Sequence | image/heif-sequence | JUMBF manifest store in a C2PA uuid box in the ISO BMFF structure |
| SVG | image/svg+xml | Base64-encoded JUMBF manifest store in the SVG metadata element |
| DNG | image/x-adobe-dng | JUMBF manifest store in a dedicated tag of the TIFF/EP image file directory (DNG is TIFF-based) |
| GIF | image/gif | JUMBF manifest store in a GIF application extension block |
| JPEG XL | image/jxl | JUMBF superbox (jumb) at the top level of the JPEG XL box structure |
| WAV | audio/wav | JUMBF manifest store in a C2PA chunk of the RIFF container |
| MP3 | audio/mpeg | JUMBF manifest store in an ID3v2 GEOB (general encapsulated object) frame |
| M4A | audio/mp4 | JUMBF manifest store in a C2PA uuid box in the ISO BMFF structure |
| AAC | audio/aac | JUMBF manifest store in a C2PA uuid box in the ISO BMFF structure (AAC audio carried in an MP4 container) |
| FLAC | audio/flac | JUMBF manifest store in a leading ID3v2 GEOB frame (MIME application/c2pa); legacy FLAC APPLICATION blocks (app id c2pa) remain readable |
| MPA | audio/mpa | Read as MPEG audio (audio/mpa is an accepted alias of audio/mpeg): JUMBF manifest store in an ID3v2 GEOB frame |
| MP4 | video/mp4 | JUMBF manifest store in a C2PA uuid box in the ISO BMFF structure |
| MOV | video/quicktime | JUMBF manifest store in a C2PA uuid box in the ISO BMFF structure (QuickTime uuid atom) |
| M4V | video/x-m4v | JUMBF manifest store in a C2PA uuid box in the ISO BMFF structure |
| AVI | video/x-msvideo | JUMBF manifest store in a C2PA chunk of the RIFF container |
application/pdf | JUMBF manifest store in an embedded file stream with AFRelationship C2PA_Manifest | |
| EPUB | application/epub+zip | JUMBF manifest store in the META-INF/content_credential.c2pa entry of the ZIP package |
| DOCX | application/vnd.openxmlformats-officedocument.wordprocessingml.document | JUMBF manifest store in the META-INF/content_credential.c2pa entry of the OOXML ZIP package |
| ODT | application/vnd.oasis.opendocument.text | JUMBF manifest store in the META-INF/content_credential.c2pa entry of the ODF ZIP package |
| OXPS | application/oxps | JUMBF manifest store in the META-INF/content_credential.c2pa entry of the OpenXPS ZIP package |
| OTF | font/otf | JUMBF manifest store in an SFNT table with the tag C2PA |
| TTF | font/ttf | JUMBF manifest store in an SFNT table with the tag C2PA |
| SFNT | font/sfnt | JUMBF manifest store in an SFNT table with the tag C2PA |
The table lists the formats with a detail page. The full matrix, including each format's accepted spellings (101 in all, counting aliases such as image/jpg), is published at GET /api/v1/capabilities/formats.
Production signing emits C2PA 2.4 by default. Of the 79 formats that sign and verify, 76 sign under that version; the rest sign under an earlier one. Verification does not depend on version.
# Sign any media file. The format is detected from the bytes.
curl -X POST https://api.encypher.com/api/v1/sign/media \
-H "Authorization: Bearer YOUR_API_KEY" \
-F "file=@content.pdf"
# The live list of formats, with sign and verify flags
curl https://api.encypher.com/api/v1/capabilities/formats