I want to build an embedded system that reads external data and logs it to a file saved in an SD card. However this system is accessed through a password and I want either the SD card or the file in it to use this password as well. How can I do it? About the file, I thought of saving it with a .CSV extension because it uses rows and columns. Can this type of files have password? Any suggestions?
To be more specific with the question: I will use a microcontroller, programmed with C language. What commands should I send to the SD card in order to be password-protected? Or, what is the format of a file in order to have an access password?
EDIT: I want to add a password so that only the user is able to open the file and read it using his/her PC.