How to Protect a File

[Revolution]

Dear Gurus,

I want to protect a file in the folder for that I Encrypt the file. It was Encrypted but it won't be safe bcz anyone can change the content so that I can't decrypt it. Now I want to Protect the File without giving permission to open or edit a file so that I used the Lock API it will lock the file.

But I want to lock the file whenever the system logs on and I have to maintain the Handle value in the memory to unlock it.

So that I need some more solutions, pls help me

Is there any other way to protect the file without being opened, edited and changed. Waiting for ur reply

[NoHero]

Well you could CreateFile() on it with SHARE_DENY_ read/write so the file is read and write protected. Just create a service booted by startup and do your lock.

The only problem: The user or a program can disable your service, to prevent this, you may create a low level API hook and/or a driver who does your trick.

[Revolution]

Thanks for ur reply,

Could u pls explain me more detail. Is there any reference link to know more about it.

Eagerly waiting for ur reply

[golanshahar]

Thanks for ur reply,

Could u pls explain me more detail. Is there any reference link to know more about it.

Eagerly waiting for ur reply

if you want sample of creating a service look at this article: Writing a Service Program (http://www.codeguru.com/Cpp/W-P/system/services/article.php/c5785/)

Cheers