Data Ownership Classifications: See the Text: Principles of Information Security p. 27 Data Owner: Person responsible for security and use of a particular set of data. Data owners are responsible for classifying data. Data owners should be high-level technology-savvy management types. Data custodian: Often this is the system administrator of the system that the data resides on. The custodian is the person who is responsible for securing the operating system, doing backups, and implementing the security policies of the organization and controlling access to the different classifications of data. Data user: End users who use the data on a day to day basis. Data users MUST also be trained on their role in keeping data secure and accurate.