Method for transmitting data and preventing unauthorized data duplication for human-machine interface device using mass storage class operating on universal serial bus

A method for transmitting data and preventing unauthorized data duplication for human-machine interface device (HID) using Mass Storage Class (MSC) operating on Universal Serial Bus (USB) simulating the HID as a USB storage device to transmit data to an external computer, the method comprising:

• a) receiving a password file by the HID, wherein the password file has a file name, and the password file records a dynamic password therein;
• b) determining whether the password file is a download password file or an upload password file according to the file name of the received password file;
• c) when the password file is a download password file, writing a password confirmation file to a File Allocation Table (FAT) by the HID upon confirming a dynamic password in the download password file is correct;
• d) receiving a download data file encrypted by the dynamic password by the HID following step c;
• e) when the password file is a upload password file, generating a random file name of an upload data file via a formula based on the dynamic password recorded in the password file;
• f) generating a plurality of substitute files via a formula based on the dynamic password recorded in the password file, wherein the plurality of substitute files have random file names;
• g) writing the upload data file and the plurality of substitute files to the FAT by the HID, thus the external computer is able to acknowledge existence of the upload data file and the plurality of substitute files upon confirming the dynamic password in the upload password file is correct;
• h) permitting a data duplication of the upload data file by the HID when a replication request of the upload data file is correct following step g;
• i) when the data duplication of the upload data file executes once, or the replication request of the upload data file is incorrect, deleting the upload data file from the FAT by the HID following step h;
• wherein the HID does not write the received password file and the download data file to the FAT thus an external computer is not able to acknowledge the download data file by accessing to the FAT.