def METHOD_NAME(
    self, data: bytes, current_time: int, iv: bytes
) -> bytes:
    utils._check_bytes("data", data)
    padder = padding.PKCS7(algorithms.AES.block_size).padder()
    padded_data = padder.update(data) + padder.finalize()
    encryptor = Cipher(
        algorithms.AES(self._encryption_key),
        modes.CBC(iv),
    ).encryptor()
    ciphertext = encryptor.update(padded_data) + encryptor.finalize()
    basic_parts = (
        b"\x80"
        + current_time.to_bytes(length=8, byteorder="big")
        + iv
        + ciphertext
    )
    h = HMAC(self._signing_key, hashes.SHA256())
    h.update(basic_parts)
    hmac = h.finalize()
    return base64.urlsafe_b64encode(basic_parts + hmac)