example of decryption about encrypted-content-encoding HOT 3 CLOSED

import base64

import http_ece
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives.asymmetric import ec
from cryptography.hazmat.primitives import serialization
from devtools import debug

vapid_encoding = 'aes128gcm'

auth = b'-xRoM3G68ZaAL2wo3peFlg'
receive_key = ec.generate_private_key(ec.SECP256R1, default_backend())
# receive_key = default_backend().derive_elliptic_curve_private_key(1, ec.SECP256R1)
p256dh = base64.urlsafe_b64encode(
    receive_key.public_key().public_bytes(
        encoding=serialization.Encoding.X962,
        format=serialization.PublicFormat.UncompressedPoint
    )
).strip(b'=')


def _prepare_vapid_key(data: bytes) -> bytes:
    """
    Add base64 padding to the end of a string, if required
    """
    data = data + b'===='[: len(data) % 4]
    return base64.urlsafe_b64decode(data)


auth_preped = _prepare_vapid_key(auth)
p256dh_preped = _prepare_vapid_key(p256dh)


enc = http_ece.encrypt(
    b'this is a test',
    private_key=ec.generate_private_key(ec.SECP256R1, default_backend()),
    dh=p256dh_preped,
    auth_secret=auth_preped,
    version=vapid_encoding,
)
debug(enc)

decoded = http_ece.decrypt(
    enc,
    private_key=receive_key,
    auth_secret=auth_preped,
    version=vapid_encoding
)
debug(decoded)