Data protecting method, mobile communication device, and memory storage device

A mobile communication device, comprising:

• a microprocessor;
• a wireless communication unit, coupled to the microprocessor;
• and
• an external device interface unit, coupled to the microprocessor, wherein a memory storage device is detachably coupled to the external device interface unit;
• and
• a security circuit, coupled to the microprocessor, and storing a first authentication information into a hidden area of the memory storage device,
• wherein the wireless communication unit receives a data packet, and the data packet comprises a data security instruction and a second authentication information;
• wherein the security circuit parses the data packet according to the data security instruction to obtain the second authentication information, and the memory storage device determines whether the second authentication information obtained from the data packet matches the first authentication information stored in the hidden area,
• wherein if the second authentication information obtained from the data packet matches the first authentication information stored in the hidden area, the memory storage device performs a data protecting operation on data stored in a storage area to prevent the data stored in the storage area from being read,
• wherein the first authentication information comprises a first digest, a first encrypted data, and a device ID of the mobile communication device,
• while storing the first authentication information into the hidden area of the memory storage device, the security circuit obtains the device ID of the mobile communication device, receives a user account and a user password to be set, encodes the user account and the user password through a one-way hash encoding unit to generate the first digest, encrypts the user account and the user password through an encryption unit to generate the first encrypted data, and stores the device ID, the first digest, and the first encrypted data into the hidden area of the memory storage device.

A memory storage device, comprising:

• a connector;
• a rewritable non-volatile memory module, comprising a hidden area and a storage area;
• and
• a memory controller, coupled to the connector and the rewritable non-volatile memory module,
• wherein the memory controller writes a device ID of a mobile communication device, a first digest, and a first encrypted data into the hidden area, wherein the first digest is generated by encoding a user account and a user password through a one-way hash encoding unit, and the first encrypted data is generated by encrypting the user account and the user password through an encryption unit,
• wherein the memory controller further receives a second digest and a second encrypted data, decrypts the second encrypted data to obtain an account and a password, decrypts the first encrypted data to obtain the user account and the user password, and determines whether the second digest matches the first digest stored in the hidden area,
• wherein when the second digest matches the first digest stored in the hidden area, the memory controller further determines whether the user account and the user password match the account and the password,
• wherein when the user account matches the account and the user password matches the password, the memory controller performs a data protecting operation on data stored in the storage area to prevent the data stored in the storage area from being read,
• wherein when a read command is received to read data stored in the storage area, the memory controller determines whether a current device ID matches the device ID stored in the hidden area,
• when the current device ID does not match the device ID stored in the hidden area, the memory controller transmits a predetermined data in response to the read command.