How to protect python code ?

Jp Calderone exarkun at
Thu Apr 3 18:56:52 CEST 2003

On Thu, Apr 03, 2003 at 09:35:49AM +0200, christophe grimault wrote:
> Hello,
> Before trying my own solutions, I wonder if someone already has a solution
> to this. We have been programming a quite large application in python and
> it contains many original algorithm and other things. The application will
> be sent to customers in a few month and since it is a commercial app, we
> need some protection against copy (illegal copies) and we need to make
> sure that critical parts of the code cannot be viewed and studied.

  Why?  Is your competition going to steal your algorithm and publish their
own software (which people will then buy exclusively, instead of yours), and
which is obfuscated infinitely better than yours, so it is impossible to
prove it is based on stolen property?

  Or are your algorithms stolen? ;)

  Protect against illegal copies?  Take a look around, there is almost no
scheme that is successful here.  People warez software, it's a shame, but
it's a fact of life.

> One way is to deliver only .pyc files, but I guess this is quite a poor
> protection, uh ?

  Defeatable in a minute or two, yes.

> An other way is to move some parts to a C API ext module and deliver only
> the .so, but this is quite time consuming ...

  Pyrex might speed it up a bit.

> Does someone has a mean to do this, knowing that we don't seek absolute
> protection, but something that discourages people that will just "try a
> little"

  Proper licensing and a tank of attack lawyers.  Alternatively, approach
your competition before the release, and offer to sell them what you think
they're going to try to steal.


Lowery's Law:
        If it jams -- force it.  If it breaks, it needed replacing anyway.
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