What could be done to avoid a VFP a .exe to be decompiled ?

It is very hard to keep VFP code from getting decompiled. There is ReFox which can expose the code very easy in the lower levels of security. In the higher levels of security, ReFox cannot expose the code from the file, but the code can be exposed from memory by a program written by Chinese hackers.

ReFox decompiles and protects the code at the same time. It depends on how you use it.

So putting it simply, there is no 100% security.

My worst suspicions are in course

My site have been accessed from China and a lot of downloads of my apps were downloaded... I checked it by ip.

Maybe they are copying all my code now.

I don't know what could be done from here.

I'm going to ask net provider if it's possible to avoid China access...

Each software appears on Torrents sooner or later... Would you sell your app in China?

People copying your app would never buy it.  BUT they can sell it which is not so good... The only way is to create new versions periodically so you are one step before them...

BTW, pirated Windows are much cheaper and they do have better support than the original version. So you have to be prepared for this situation...

I am not sure if your net provider can do something for you... To access your site from China via servers in the US is not so difficult...

But, as a workaround I'm going to apply some difficulties by myself that couldn't be related here  some spyes maybe could read <|- )

Maybe if I obtain your personal e-mails I'm going to tell you what I'm doing....

My nickname plus hotmail.com.

Yes, to have variables and fields like mmmnnmnm, nmmnnmmm, mmnnmnn, etc. across the app is good idea. I've been thinking about such app scrambler BUT it could just invoke some descrambler development...

My address is in my profile here.

There are some good obfuscation programs for PHP. I never saw one for Fox.

Thank you for the guidance. I'm keep struggling with this problem...