Reasons for derogating the exercise of the Articles 15 – 20
Where, in cases referred to in paragraph 1 of this Article, the controller is able to demonstrate that it is not in a position to identify the data subject, the controller shall inform the data subject accordingly, if possible. In such cases, Articles 15 to 20 shall not apply except where the data subject, for the purpose of exercising his or her rights under those articles, provides additional information enabling his or her identification.
Chapter II, Article 11, Paragraph 2
Regulation's subject matter
Processing which does not require identification (Article 11, Chapter II)