Abstract: A method and a system for protecting data of a storage unit are disclosed for use in a data processing device. A user identification module encodes and encrypts a password preset by the user and stores the encoded and encrypted password into the storage unit. Next, the user identification module encodes and encrypts partition table data read from a memory unit and stores the encoded and encrypted partition table data in a predetermined location of the storage unit. Then, the user identification module deletes the partition table data stored in the memory unit. Finally, when the user re-starts power of the data processing device and inputs a password consistent with the preset password, the user identification module decodes and decrypts the partition table data stored in the storage unit and writes the decoded and decrypted partition table data to the memory unit to thereby perform booting operation.