Openness Principle Offenheitsprinzip Openness Principle Principio de apertura Principio de apertura Principe d'ouverture עקרון הפתיחות खुलापन का सिद्धांत オープンネスの原則 Princípio da abertura 开放原则 Openness is the privacy principle that there should be a general policy of openness about developments, practices and policies with respect to personal data. Means should be readily available of establishing the existence and nature of personal data, and the main purposes of their use, as well as the identity and usual residence of the data controller.