closed source

[Werner Schiendl]

Hi,

Milos Prudek wrote:

> 
> Is this protection implementable?
> 

Some points that come to mind.

Personally I think C is still harder to decompile than Python (or for 
that matter any VM based language like Java or .NET IL).

The reason is, that these VMs usually have much higher level constructs 
than plain x86 assembly language (create object, access member, etc. 
have their own opcode)

So you could write an extension module containing some part of the logic 
and also the protection algorithm. Having only the protection in the C 
extension is counter-productive, as it makes it even simpler to crack. 
So be sure to add some logic vital to your application here.


Another point would be that I'd use some sort of strong encryption for 
the key, similar to PGP signed mail messages. This does not prevent 
actually cracking the software, but it's close to impossible to write a 
key generator for it.

In addition, be sure to add the licensee's name in plain text in the 
licence - nobody will give away such a license file, right?


Anyway you should be aware of what the other's in this thread said: 
there is no real way of protection *except* not giving the software out 
of your hands (i. e. make it a web service and only hand out a client).


hth

Werner