Encryption / Decryption (VB-Excel Macro)

[dilipsshah]

I have written one "TOOL" in excel which has two Excel files. "file1" and "file2".
Initially I want to check if file 1 and file 2 both are absent; otherwise say
'Error Occured'.
It should then get PC registration - add some standard string to it - fold it - save in toolset directory with a counter of 01 in encrypted form as a hidden file (file 1). Also save same file with different name in some other standard directory (that should always exist on any PC) in some other encrypted form as a hidden file (file 2).

The "TOOL" would work only if this hidden file 1 is there, decrypted to give same PC registration as user's PC and counter is less than some agreed value (defined in code as constant - say 50) AND PC date is less than 31/07/2005 AND file 1 and file 2 (after decryption) are same. Otherwise it should just say 'Error Occured' and exit - should not say anything more at all.

Every time "TOOL" is opened - it should increment this count and save the file (both file 1 and 2) without any messages - any error say 'Error Occured'. Of course this can be broken but would at least provide a deterrent. Two files are to confuse people if they try and delete one and hack the process - mostly one would try and hack file 1 as it would be very obvious. All depends upon creating file 2 in a directory other that target directory (which is hardcoded) - which is some standard 'always existing directory'.

How can i do this ?
Any hints ??
please help me ASAP as this is a bit urgent stuff..
Thanking you in anticipation.

[gwlco]

I am not certain if this will help but I use a product from Concept Software:

http://www.softwarekey.com/

This product uses a license file and a number of alias files and can detect if anyone has tried to overide the mechanism. Contact me if you have any questions at: Gary Little