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https://github.com/numbersprotocol/numbers-c2pa
https://github.com/numbersprotocol/numbers-c2pa
Last synced: about 2 months ago
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- Host: GitHub
- URL: https://github.com/numbersprotocol/numbers-c2pa
- Owner: numbersprotocol
- License: mit
- Created: 2021-09-27T05:41:48.000Z (about 3 years ago)
- Default Branch: main
- Last Pushed: 2024-06-12T07:53:25.000Z (7 months ago)
- Last Synced: 2024-09-18T00:45:36.697Z (3 months ago)
- Language: Python
- Size: 268 KB
- Stars: 1
- Watchers: 3
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# numbers-c2pa
## Setup
Install Rust
```bash
$ curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
```
Install c2patool
```bash
$ cargo install c2patool
```
Install numbers-c2pa
```
$ python3 -m pip install git+https://github.com/numbersprotocol/numbers-c2pa.git
```
## Usage
C2PA Injection
```python
from datetime import datetime
from numbers_c2pa import create_c2pa_manifest, inject_file
if __name__ == '__main__':
with open('examples/es256_private.key') as f:
private_key = f.read()
with open('examples/es256_certs.pem') as f:
sign_cert = f.read()
manifest = create_c2pa_manifest(
nid='this is nid',
creator_public_key='this is creator public key',
asset_hash='this is sha256hash',
date_created=datetime.now(),
location_created='123.123, 45.45',
date_captured=None,
)
inject_file(
'examples/numbers.png',
manifest=manifest,
private_key=private_key,
sign_cert=sign_cert,
)
# examples/numbers-c2pa.png will be created
# Upload file to https://verify.contentauthenticity.org/inspect to view C2PA data
```
Read C2PA data
```python
from numbers_c2pa import read_c2pa_file
if __name__ == '__main__':
c2pa_json = read_c2pa_file('examples/numbers-c2pa.png')
print(c2pa_json)
```
## Create self-signed certificate with intermediate CA
According to [c2patool](https://github.com/contentauth/c2patool#appendix-creating-and-using-an-x509-certificate) readme:
> Both the private_key and sign_cert must be in PEM format. The sign_cert must contain a PEM certificate chain starting with the end-entity certificate used to sign the claim ending with the intermediate certificate before the root CA certificate. See the sample folder for example certificates.
Using a intermediate CA certificate is required.
## Updated steps
Create end-entity and intermediate private keys
```bash
openssl ecparam -genkey -name prime256v1 -noout -out intermediate_ca.key
openssl ecparam -genkey -name prime256v1 -noout -out end_entity.key
```
Create intermediate cert
```bash
openssl req -x509 -new -key intermediate_ca.key -out intermediate_ca.crt -subj "/CN=Numbers Intermediate CA" -days 365 -sha256
```
Create `end_entity_csr.conf` file
```conf
[ req ]
default_bits = 2048
prompt = no
default_md = sha256
req_extensions = v3_req
distinguished_name = dn
[ dn ]
C = US
ST = California
L = San Fransisco
O = Numbers Protocol
OU = Numbers Protocol
CN = Numbers Protocol
[ v3_req ]
basicConstraints = CA:FALSE
keyUsage = digitalSignature, keyEncipherment
extendedKeyUsage = timeStamping
subjectAltName = @alt_names
[ alt_names ]
DNS.1 = numbersprotocol.io
DNS.2 = www.numbersprotocol.io
```
Create end-entity CSR
```bash
openssl req -new -key end_entity.key -out end_entity.csr -config end_entity_csr.conf
```
Create end-entity certificate
```bash
openssl x509 -req -in end_entity.csr -CA intermediate_ca.crt -CAkey intermediate_ca.key -out end_entity.crt -days 365 -CAcreateserial -extfile end_entity_csr.conf -extensions v3_req -sha256
```
Combine certificate chain
```bash
cat end_entity.crt intermediate_ca.crt > certificate_chain.pem
```