A differential backup is a data protection method that saves only the changes made since the last full backup. This means that if you perform a full backup on Sunday, a differential backup on Monday will include all changes made since Sunday. This approach reduces the amount of data stored compared to full backups, making it quicker and more efficient. When restoring data, a differential backup requires the last full backup and the most recent differential backup. This simplifies the recovery process, as you only need two sets of data instead of multiple incremental backups. This method is commonly used in data management systems to ensure data integrity and minimize downtime.