Recital 34

Biometric data, as defined in Article 4(14) of Regulation (EU) 2016/679, means processing of certain characteristics of a natural person through a specific technical means and which allows or confirms the unique identification of that person. The notion of biometric data includes two distinct functions, namely the identification of a natural person or the verification (also called authentication) of his or her claimed identity, both of which rely on different technical processes. The identification process is based on a ‘one-to-many’ search of the data subject’s biometric data in a database, while the verification process is based on a ‘one-to-one’ comparison of biometric data provided by the data subject, who is thereby claiming his or her identity. Derogating from the prohibition to process biometric data under Article 9(1) of the Regulation should also be allowed where the verification of the claimed identity of the data subject is necessary for a purpose pursued by the controller, and suitable safeguards apply to enable the data subject to have sole control of the verification process. For example, where the biometric data are securely stored solely at the side of the data subject or are securely stored at the side of the controller in a state-of-the-art encrypted form and the encryption key or equivalent means is held solely by the data subject, that processing is not likely to create significant risks to his or her fundamental rights and freedoms. The controller does not gain knowledge of the biometric data or only for a very limited time during the verification process.