Package: c2pa-python
C2PA PythonPython bindings for the C2PA Content Authenticity Initiative (CAI) library.This library enables you to read and validate C2PA data in supported media files and add signed manifests to supported media files.WARNING: This is an early prerelease version of this library.  There may be bugs and unimplemented features, and the API is subject to change.InstallationInstall from PyPI by entering this command:pip install -U c2pa-pythonThis is a platform wheel built with Rust. If your platform is not already supported,
see the development section for info on how to build from source.## Usage

### Import

Import the C2PA module as follows:

```py
import c2paRead and validate C2PA data in a fileUse theread_filefunction to read C2PA data from the specified file:json_store=c2pa.read_file("path/to/media_file.jpg","path/to/data_dir")This function examines the specified media file for C2PA data and generates a JSON report of any data it finds. If there are validation errors, the report includes avalidation_statusfield.  For a summary of supported media types, seeSupported file formats.A media file may contain many manifests in a manifest store. The most recent manifest is identified by the value of theactive_manifestfield in the manifests map.If the optionaldata_diris provided, the function extracts any binary resources, such as thumbnails, icons, and C2PA data into that directory. These files are referenced by the identifier fields in the manifest store report.NOTE: For a comprehensive reference to the JSON manifest structure, see theCAI manifest store reference.Add a signed manifest to a media fileUse thesign_filefunction to add a signed manifest to a media file.result=c2pa.sign_file("path/to/source.jpg","path/to/dest.jpg",manifest_json,sign_info,data_dir)The parameters (in order) are:The source (original) media file.The destination file that will contain a copy of the source file with the manifest data added.manifest_json, a JSON-formatted string containing the manifest data you want to add; seeCreating a manifest JSON definition filebelow.sign_info, aSignerInfoobject instance; seeGenerating SignerInfobelow.data_diroptionally specifies a directory path from which to load resource files referenced in the manifest JSON identifier fields; for example, thumbnails, icons, and manifest data for ingredients.Create a SignerInfo InstanceASignerInfoobject contains information about a signature.  To create an instance ofSignerInfo, first set up the signer information from the public and private key.pemfiles as follows:certs=open("path/to/public_certs.pem","rb").read()prv_key=open("path/to/private_key.pem","rb").read()Then create a newSignerInfoinstance using the keys as follows, specifying the signing algorithm used and optionally a time stamp authority URL:sign_info=c2pa.SignerInfo("es256",certs,priv_key,"http://timestamp.digicert.com")For the list of supported signing algorithms, seeCreating and using an X.509 certificate.Creating a manifest JSON definition fileThe manifest JSON string defines the C2PA manifest to add to the file.manifest_json=json.dumps({"claim_generator":"python_test/0.1","assertions":[{"label":"c2pa.training-mining","data":{"entries":{"c2pa.ai_generative_training":{"use":"notAllowed"},"c2pa.ai_inference":{"use":"notAllowed"},"c2pa.ai_training":{"use":"notAllowed"},"c2pa.data_mining":{"use":"notAllowed"}}}}]})DevelopmentIt is best toset up a virtual environmentfor development and testing.To build from source on Linux, install curl and rustup and set up pythonFirst update aptapt updateInstall Rustcurl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
source "$HOME/.cargo/env"Install Python, pip and venvapt install python3
apt install pip
apt install python3.11-venv
python3 -m venv .venvBuild the wheel for your platformsource .venv/bin/activate
pip install maturin
pip install uniffi-bindgen
python3 -m pip install build
pip install -U pytest

python3 -m build --wheelManyLinux builddocker run -it quay.io/pypa/manylinux_2_28_aarch64 bash
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
source "$HOME/.cargo/env"
export PATH=/opt/python/cp312-cp312/bin:$PATH
pip install maturin
pip install venv
pip install build
pip install -U pytest

cd home
git clone https://github.com/contentauth/c2pa-python.git 
cd c2pa-python
python3 -m build --wheel
auditwheel repair target/wheels/c2pa_python-0.4.0-py3-none-linux_aarch64.whlTestingWe usePyTestfor testing.Run tests by entering this command:source .venv/bin/activate
maturin develop
pytest
deactivateExampleRun the example code like this:source .venv/bin/activate
maturin develop
python3 tests/training.py
deactivateSupported file formatsExtensionsMIME typeavivideo/msvideo,video/avi,application-msvideoavifimage/avifc2paapplication/x-c2pa-manifest-storedngimage/x-adobe-dngheicimage/heicheifimage/heifjpg,jpegimage/jpegm4aaudio/mp4mp4video/mp4,application/mp4movvideo/quicktimepngimage/pngsvgimage/svg+xmltif,tiffimage/tiffwavaudio/x-wavwebpimage/webpChange Notes:Version 0.3.0 changes:
There are some breaking changes to align with future APIs:C2paSignerInfomoves thealgto the first parameter from the 3rd.c2pa.verify_from_file_jsonis nowc2pa.read_file.c2pa.ingredient_from_file_jsonis nowc2pa.read_ingredient_file.c2pa.add_manifest_to_file_jsonis nowc2pa.sign_file.There are many more specific errors types now, and Error messages always start with the name of the error i.e (str(err.value).startswith("ManifestNotFound")).The ingredient thumbnail identifier may be jumbf uri reference if a valid thumb already exists in the active manifest.Extracted file paths for read_file now use a folder structure and different naming conventions.LicenseThis package is distributed under the terms of both theMIT licenseand theApache License (Version 2.0).Note that some components and dependent crates are licensed under different terms; please check the license terms for each crate and component for details.Contributions and feedbackWe welcome contributions to this project.  For information on contributing, providing feedback, and about ongoing work, seeContributing.