def METHOD_NAME(size):
    """
    Return a string of ``size`` random bytes. Returned string is suitable for
    cryptographic use.
    :param size: Size of the generated string.
    :type size: ``int``
    :return: Random string.
    :rtype: ``str``
    """
    value = os.urandom(size)
    value = binascii.hexlify(value)
    value = value.decode("utf-8")[:size]
    return value