Thank you, but you mentioning is not the detail, somebody who contacts labVIEW will know it,

I want to know what its principle and program component, Yes, the program would be used at WindowsXP OS, and I have downloaded it from website, it works, but I don't know how it made(it is not made by labVIEW). and I would like to make one with labVIEW to simulate that sample, and I have learnt more about folder protected knowadge, simply, change the target's format to printer or any hidden file's format. as you enter correct password, and restore file original format.