Abstract: The various implementations described herein include methods and systems of data governance. In one aspect, a method of purging backup data includes obtaining a database table having a corresponding data policy and generating an encrypted version of the database table by applying an encryption key, including encrypting at least a portion of the database table. The method further includes identifying an expiration date for the encryption key based on the data policy, and storing the encryption key, the expiration date, and an encryption identifier for the encryption key in an encryption table. The method also includes receiving a command to back up the database table and, in response to the command, generating a backup of the encrypted version of the database table. The method further includes storing the backup and, when a current date is at least the expiration date for the encryption key, deleting the encryption key.