A data protection system is disclosed. The data protection system comprises a cloud management platform and at least one data storage device. The cloud management platform includes a database stored with at least one key. The data storage device includes a data storage unit, a microprocessor, and a network communication component. The microprocessor is communicated with the cloud management platform by the network communication component. The data storage unit comprises a controller and a plurality of flash memories. The flash memories store a plurality of encrypted data. The microprocessor sends a key extraction request including a unique code to the cloud management platform. The cloud management platform selects the key matching to the unique code in the key extraction request from the database, and transmits the selected key to the data storage device. The controller of the data storage device decrypts the encrypted data by the key.