def check_keystore_json(jsondata):
    """Check if ``jsondata`` has the structure of a keystore file version 3.

    Note that this test is not complete, e.g. it doesn't check key derivation or cipher parameters.

    :param jsondata: dictionary containing the data from the json file
    :returns: `True` if the data appears to be valid, otherwise `False`
    """
    if 'crypto' not in jsondata and 'Crypto' not in jsondata:
        return False
    if 'version' not in jsondata:
        return False
    if jsondata['version'] != 3:
        return False
    crypto = jsondata.get('crypto', jsondata.get('Crypto'))
    if 'cipher' not in crypto:
        return False
    if 'ciphertext' not in crypto:
        return False
    if 'kdf' not in crypto:
        return False
    if 'mac' not in crypto:
        return False
    return True