SD Card Proprietary File Format

Hi All,

I'm making a data logging device using Arduino Uno Rev3 and an Adafruit SD Card data logger shield and Real Time Clock.

I'm currently saving the files as text files using logfile.print() commands.

I don't want people editing the files after they have been created and moved onto a PC using the SD card.

I'm interested in stopping someone with basic computer knowledge from editing the file.

So my question is: Is there anyway to save files to the SD card from my data logger in some Proprietary File Format so that I can stop the average computer user editing the file?



Set the readonly attrib. Make it hidden. Give it a misleading file extention.
Use win7s file encrypting.

Make them binary, not text.

ROT13 them.

Use octal, hex or base 36.

Thanks guys, I'm still learning arduino so don't understand, how do I change the read only property and how can i save as a binary file?