The processing of personal data is only lawful if there is a legal basis for the processing. Pursuant to Article 6 (1) lit. a - f DSGVO, the legal basis for processing may be in particular:
a) The data subject has given consent to the processing of personal data concerning him or her for one or more specific purposes;
b) the processing is necessary for the performance of a contract to which the data subject is party or for the implementation of pre-contractual measures taken at the data subject's request;
c) processing is necessary for compliance with a legal obligation to which the controller is subject;
d) processing is necessary in order to protect the vital interests of the data subject or of another natural person;
e) processing is necessary for the performance of a task carried out in the public interest or in the exercise of official authority vested in the controller;
f) processing is necessary for the purposes of the legitimate interests of the controller or of a third party, except where such interests are overridden by the interests or fundamental rights and freedoms of the data subject which require the protection of personal data, in particular where the data subject is a child.