Read the contents of a covid pass

pass.py

import json
import sys
import zlib

import base45
import cbor2
import cv2
from cose.messages import CoseMessage

# initialize the cv2 QRCode detector
detector = cv2.QRCodeDetector()

if len(sys.argv) > 1:
    img = cv2.imread(sys.argv[1])
    data, bbox, other = detector.detectAndDecode(img)
    print(data)
    print(data, bbox)
    payload = data[4:]

else:
    cap = cv2.VideoCapture(0)

    while True:
        _, img = cap.read()

        # detect and decode
        data, bbox, other = detector.detectAndDecode(img)
        # check if there is a QRCode in the image
        if data:
            payload = data[4:]
            break

        cv2.imshow("QRCODEscanner", img)
        if cv2.waitKey(1) == ord("q"):
            break

    cap.release()
    cv2.destroyAllWindows()


# decode Base45 (remove HC1: prefix)
decoded = base45.b45decode(payload)

# decompress using zlib
decompressed = zlib.decompress(decoded)

# decode COSE message (no signature verification done)
cose = CoseMessage.decode(decompressed)

# decode the CBOR encoded payload and print as json
print(json.dumps(cbor2.loads(cose.payload), indent=2))