DCC Utils

Python library to decode the EU Covid-19 vaccine certificate, as specified by the EU.

Setup

pip install dcc-utils

Make sure zbar is installed in your system

For Mac OS X, it can be installed via brew install zbar
Debian systems via apt install libzbar0. Source
Fedora / Red Hat dnf install zbar

Usage

Parse DCC

This library takes an image with a QR code or a raw repr. of a vaccine certificate as the parameter and will show the certificate's content.

from dcc_utils import dcc

dcc_from_img = dcc.from_image("/my/certificate/path")
dcc_from_raw = dcc.from_raw("HC1:6BF...FTPQ3C3F")

Then you can access to payload and kid

assert dcc_from_img.kid == "53FOjX/4aJs="
assert dcc_from_img.payload["v"][0]["ci"] == "URN:UVCI:01:FR:W7V2BE46QSBJ#L"

👉🏻 payload follows EU Digital COVID Certificates JSON Schema Specification

from_image and from_raw methods may rise DCCParsingError

from dcc_utils.exceptions import DCCParsingError

Validate DCC digital signature

signature = b"""
-----BEGIN CERTIFICATE-----
MIIIAjCCBeqgAwIBAgIQAnq8g/T
-----END CERTIFICATE-----
"""
assert my_dcc.check_signature(signature)

check_signature method may rise DCCSignatureError

from dcc_utils.exceptions import DCCSignatureError

Evaluate CertLogic business rules

With dcc-utils you can evaluate business rules against a DCC

from dcc_utils import rule, dcc

my_dcc = dcc.from_image("/my/certificate/path")
my_rule = rule.from_file("/my/rule.json")
print(my_rule.description["en"])
my_rule.evaluate_dcc(my_dcc) # True or False

evaluate_dcc accepts extra variables as a second parameter, e.g. validationClock

import datetime
clock = datetime.datetime(2022, 10, 10, 0, 0, tzinfo=datetime.timezone.utc)
my_rule.evaluate_dcc(
    my_dcc,
    {
        "validationClock": clock,
    },
)

you can also load rules from JSON (from_json), useful to evaluate rules exposed on a server

my_rule = rule.from_json({...})

from_file and from_json method may rise DCCRuleError

from dcc_utils.exceptions import DCCRuleError

Dev setup

Install dependencies using pip:

pip install -r requirements-dev.txt

Run tests

make test

EU Digital COVID Certificate Specifications

What's in a EU Digital COVID/Green Certificate?

Value Sets for Digital Green Certificates https://ec.europa.eu/health/sites/default/files/ehealth/docs/digital-green-certificates_dt-specifications_en.pdf
JSON schema: https://github.com/ehn-dcc-development/ehn-dcc-schema

Sample data

Digital Green Certificate Gateway (DGCG) samples for all participating countries: https://github.com/eu-digital-green-certificates/dgc-testdata

Credits

Parts of this code are adapted from vacdec project.

License

This library is available under the MIT license.

italia/dcc-utils